Chuffing ell..
I noticed this morning with the frost that the front and rear demister don't work. I've done a bit of research and in a minute I'm going to remove the rear spoiler to check the connection. A relay clicks when the button is pressed so something is happening.
When i pressed the button for the front demister the overhead light dimmed for a second (the door was open at the time) but the frost didn't melt within a minute or two. Apart from fuses what else do I need to look for?

How healthy is your battery? The reason I ask is when I got mine, the heated screen wasn't working, shortly afterwards the battery gave up the ghost. New battery and everything works. This time of year the electrical draw is as high as it's going to get with heated seats, screens, heater on full, lights on etc, and from what I understand, the car will decide it can't power everything so doesn't.

I think (hope) the battery is OK. Its just had to have a new alternator. I reckon I may just buy a new battery soon anyway.
I tried to get the spoiler off today but a combination of cold, rain, light and not really knowing how it comes off made me give up and go and hang a 30kg oak door instead..
Maybe tomorrow..

Have a look here:
http://www.rrsport.co.uk/forum/topic29082.html

 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

This car is not going to plan.. Ive also noticed that the passenger side Air vents only push out cold air while the driver side is nice a nd and warm.
Whats going on there then..

Thanks for that link. Low and behold the connection under the spoiler was all corroded so I cut it out and reconnected the wires.
As for the front demister I don't know yet along with the stuck heater vent heat differential.

My left front demister failed and thanks to another forum member, I checked the big J fuses in the Engine bay fuse box and sure enough, it was blown. Apparently it’s a known issue and a replacement of another design is recommended. My original had 2 fuseable links whereas the replacement was one heavier gauge link. Works fine now. 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