No fuel tank vacuum issues after checking yesterday and so I’ve still not found the solution, and to give it a go I fitted a new Lucas idle control valve which has made it worse.
On a test run yesterday the car now stops on the flat too, but what I found, which would possibly explain why I thought it was just hill related, is that it stops after being on over run for a while such as purely engine brake slowing for a roundabout on a faster road. If I stop quickly with little to no over run it’s fine.
The actual moment it dies is just as I’m coming to a halt and depress the clutch at which moment the revs drop and do not come up again.
The car starts immediately after stopping, it idles at 800 and if I blip the throttle the revs dip to just below then come back up to 800.
Anyone got any thoughts what to look at next?