Can anyone give me some ideas on what might be the cause, or how to trace a battery draining fault, RR Sport V8 Diesel, 2007. Drain is, I think, about 6mA.

A fully charged, good condition battery (new in March 2020) will drain, if the car is unused, in 3-4 days. If I use the car, I don't get the problem, so I assume the alternator is OK. I get 13 volts dc across the posts with the engine running. Ive tried fitting a test lamp between one of the battery posts and the lead, then pulling the fuses individually but the lamp stayed on throughout. Everything in the car works fine but I very occasionally the master switch for the (4) windows doesn't operate the 3 for the passengers - all 4 of the the individual door switches work.

Some ideas would be much appreciated.

6 ma won’t flatten it in the time you say.
Even 60ma won’t.

There are guides on here.

13v sounds low for an RRS straight after starting
15v is usually seen

As Andy says, 13V is too low,, a constant 13V would not fully charge a 12V battery. I see 14.65 on mine,, it will vary but mostly it is the higher value.

It might be worth having a full test put on the charging system,, the battery might be new but if it is not being charged properly it will only hold a percentage of its full capacity,,,, even if it does show 12.6V at rest. ( 12.6V being a fully charged battery). 2010 RRS, TDV8
bali Blue / colour coded
side steps / flappy paddles
black perforated leather
22" overfinch
heated everything, TV,fridge ...... now with gold calipers and mud flaps !( black mud flaps that is) !!
Many years ago,,,,, 1955 series 1 landie , sometimes wish I had kept it

Is it a calcium battery and is it a YUASA by chance? 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Thanks for the replies, I bow to your superior knowledge. I might have mis-read the ammeter when looking at the rate of drain, similarly, I might be mistaken on the charging voltage. However, what I do know is if I re-charge the (Exide) battery and disconnect it, for any period of time, there is no loss. If I leave it connected, after just a few days, the battery is flat. I must therefore assume that something on the car is pulling a current - but I don't know what and where to start looking. I shall repeat the test lamp/pulling fuses exercise in case I missed somehting first time I did it. I used the car this morning and almost everything works correctly - the drivers door window wouldn't, initially close up the the top, it would re-bound down as if the safety function had kicked in. Has anyone had similar window problems?

The problem with some new batteries and what I’ve had with YUASA silvers (calcium), one they’ve gone flat, they are shot. They only ever get a surface charge. My CTEK would show green and fully charged but as soon as I tried to start the car, the charger would drop back to 3. It could we worth just getting that battery checked for peace of mind because if it’s a calcium battery, it will be knackered even at 4 months old. 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

I originally thought the battery must be faulty. I bought it on eBay and contacted the supplier and returned it for checking. They've confirmed there is no fault - so the fault must be on the car - and this is confirmed as I get the same symptoms on another battery borrowed from another vehicle.

BTW, the supplier is TAYNA BATTERIES and their support has been first class, I would recommend them for value and service.

see here for more info and a link

https://www.rrsport.co.uk/forum/topic55280.html?highlight=battery

What’s your timeline,

i.e. purchase batt, went flat and sent it back. Received it again with no fault and it’s gone flat a 1/2 dozen times since?

Reason I ask is that you may have a fault with the car which after the batt going flat once was ok but after a 1/2 dozen more times it could be toast and you have 2 separate faults that you’re trying to chase.

Give it a charge and then put a load on it like starting the engine and see what the charger says. If you google Calcium batteries you’ll find lots of info regarding the pros and cons. 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph

Regarding your window problem,,, Keep dabbing on the switch until you get the window right too the top,, then hold the switch in the up position for 3 secs and release,,, your window should work correctly after that.
Regarding the battery,,, bite the bullet and visit somewhere that can put proper test on the battery and charging system you will then know where you stand. If you have a 2 part tailgate a common issue causing a battery drain is the switch on the upper glass section,, make sure there is no water ingress. 2010 RRS, TDV8
bali Blue / colour coded
side steps / flappy paddles
black perforated leather
22" overfinch
heated everything, TV,fridge ...... now with gold calipers and mud flaps !( black mud flaps that is) !!
Many years ago,,,,, 1955 series 1 landie , sometimes wish I had kept it

Have you checked your upper tailgate switch, this was the cause of my battery drain and many others on here.Have a look at my posts regarding battery drain

my rear window defroster caused my battery to run flat. Disconnected it, and all good. Wiring had gone bad on it.

Worth trying above suggestions, but it could be anyplace. It took an Auto electrician 3 days to find the parasitic drain on my car.
If you can't find it don't use the main dealer, use a proper Auto electrician.

Thank you all for your comments, I've now learnt a lot more about the problem. With the engine running, the charge from the alternator is over 14.5V, the battery stays OK if I use the car - no fault here. The tailgate glass switch has collapsed - I've fixed this. The windows work OK at the moment - as does everything else.
I've tried 2 test lamps in series between the positive post on the battery and the power lead to the fuse box (disconnected from the lead to the alternator). One lamp, with a low wattage bulb, glows constantly. The other, with a brake lamp bulb, pulses on and off. I've tried pulling the fuses individually again but none interrupt this pulsing.
I can't think what might be causing this pulsing, anybody got any ideas?

Thanks again.

Have you also pulled the relays? Maybe it’s a bad relay cycling? You could try pulling one at a time. 2019 5.0 SC SVA (Current)
2012 5.0 SC AB. Sadly written off by a campervan
23 plate Focus ST (Current)
1942 VEP Ford GPW Jeep (Willys) (Current)
1943 Whites M16 Halftrack (Current)
16 plate Eurofighter Typhoon, 2 x Eurojet engines with 20,000lbs thrust each. 1380mph