Hi - The gaskets are not that expensive to do, had mine done recently and only worth doing if he has genuine vauxhall replacements (seems to be the general view on here) my local garage charged me £100 parts and labour. They also replaced my spark plugs for just the cost of the plugs but would be well worth doing this too if you bought this one.
Oh and I would be wary of ebay cars, bought a few myself over the years and have been lucky that I haven't bought a lemon - yet! but trust the gut instinct, for instance look at the background and ask yourself why this guy hasn't taken the pics at this house - instead looks like a retail park so he can't argue that he going for the picturesque viewpoint
and he is now barracking the "watchers" for not bidding, I always think thats a bad sign personally but my point is always try and go and see the car before bidding. Or buy off here from a long term member for a little extra peace of mind - I think it's Josheywatt that always seems to have some very nice examples.
Darren
Darren