Update:

The new ignition switch arrived today. spent 15-20 minutes putting it in (it was alot more fiddly than I expected it to be)....I wont know if it resolved the issue until well...until it doesn't die again i guess...Having said that, it may well just be the placebo effect, but I can hear the in tank and in line pumps alot louder now (I could never really hear them at all before), and power delivery seems significantly smoother and stronger) again, may very well just be the placebo effect...Spent probably 3-4 hours driving around and doing christmas shopping at various different places with no issue whatsoever...so hopefully thats sorted it.

Either way I have ordered a new glow plug control module