I made 2 tools, one to pressurise the system and another to open the valves in the block. I then opened the bleed screws on the ARB and had a brake bleed kit pipe on the bleed nipple to observe the fluid. Probably cost about £20 to make the tools from scrap and purchased parts. 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

Does it sound like that could be the problem? seems logical to me but how would a well known indy not suss that out? but then again.....

Just been out to have another look. Started car and removed reservoir cap. A fair few air bubbles are appearing and more worryingly, the fluid is a fair bit below minimum! I thought that this could be caused by air in system been replaced by fluid so rang indy up again and explained my findings and carefully suggested that it might still need bleeding. The service guy said he remembered the technician spending ages bleeding it. But, i offered, how can you explain the loss of fluid with so visible signs of leaks? to which he replied "they can be a bit below minimum without any effect"! I told him that as £700.00 was charged for strip, clean & rebuild of valve block, the very least i would have expected was for the correct amount of fluid to be put in! He is having a word with the technician and getting back to me.

When I replaced my front pipes, I put fluid in the system and ran it for a journey, topped the reservoir up and repeated until it settled at full every time. 2 weeks later when I finished making the tools I bled the system and got more air out. Not a lot but it was there. I never got any warnings though. I’ve been researching the wiring and can’t find a diagram with the ARC but did work out some parts using the RRS ELECTRICAL REFERENCE manual. 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

Indy rang back this afternoon. Said that technician drained some fluid from reservoir as looked to be over maximum. Told me to check again with no engine running, i did and it was ok. They said the bubbles are normal and were 99% sure the problem would be with the valve block and they are mega bucks and a PITA to fit as getting them to seal is a pig. So basically, i am shafted!

I was just looking into where the pressure sensor was and it does look like it’s in the valve block.

If you’re a reasonably competent mechanic you could buy a second hand unit off eBay (they are on there) and fit that. I had a few minor probs with getting my pipes out but they did move when I got a good tool on them. If you can’t get them to seal you could try what a disco owner has done on you tube and fitted standard Hydraulic connectors on to the block so no more leaks. When I did my front pipes it was a case of pay a grand or more to lift the body or £8 for 4 x 3000bar connectors. Guess what I chose and it’s never leaked once.

I would expect the block modification and fit to take no more than a day with basic tools and experience, it may not be ideal but should work equally as well. 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 that. It looks like i might have to go down this route. The indy mentioned having trouble getting new collets to seal? Is that why the disco guy changed the connectors?
I will start looking for any posts/articles to help and obviously try locate a valve block.

Yes those collets are plastic and need to be almost perfect and so does the pipe they seal onto. If they are a bitch to get out they can be damaged, I was lucky that my tool worked and they weren’t to tight.

The disco guy tapped the holes for the pipes and put in male unions and then fitted female unions on the pipes. Some of the salvage ones on eBay come with the cut Stubbs of the pipes still on them (and look in good nick) so there could be spare collets if needed. If you can get away without modifying the block then it’s a bonus. 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

Well, finally got ACE problem sorted! Took it to Maltings offroad near Doncaster. They removed the ACE system completely and reverted back to standard with new parts. No more Red light and 'bong bong' and no effect on ride either. Cost £1100.00 + £40.00 for Mot.
However, on driving home, after 40 miles, now got 'transmission fault' warning and park brake fault warning and Yellow brake shoe light on! I am mortified to say the least and my son will probably take a sledge hammer to the biggest moneypit this side of HS2!!!
Hopefully, it might be just something to do with the removal/replacement of parts for ACE system?