Thanks for the thoughts. Appreciated
I'll give her a run with the filler cap released, it may help with elimination, doubt it can harm. Good to know a ticking noise is normal, one of the symptoms of a failing solenoid valve is a loud frequent ticking noise so I was a little concerned. Yes, I gave her a run to circulate the stabiliser before laying up the car. Damp is unlikely as the garage is heated and there's a dehumidifier in there. I'm not sure how fuel contamination or electrical issues could reveal in these symptoms, which are repeatable - long run from cold or if a period of time is left before restarting, shorter runs if restarted immediately after the first stall - but I'll keep an open mind.
