Before I changed my injector seals, mine was a pig to start, cut out after idling for 5-10 mins.
Then needed a fuel purge to re-start.
So as Sierrafery says, if it starts after a purge, its 99% injector seals.
Start your fuel purge, then go and make a cup of tea! Leave it at least 5-10 mins before starting.
Also double check your oil level! But it sounds like the copper fire seals rather than the O rings.
A decent garage will do them for not a lot of money, its an hours work. BUT be careful if they start making comments like "ahh its your injectors mate...etc"!
Mark