Thanks for the replies fellas... very helpful.
I did put petrol in it and I must say its been very frugal... doesn't appear to have used any at all so far.
I imagine the battery is well charged... can't actually check it right now so will continue to imagine.
The vapour lock theory sounds plausible, I've not had it running but its quite warm here today. I'll perhaps look into investing in a hand fuel primer inline and maybe an electric fan.
(and hopefully a non imaginary van to put them in)