craftgrrl | silly question? probably

hello m'dears, I've had a browse through the FAQ but not spotted anything really that answers my query, so I'm throwing it over to you. If however it's covered from A - Z in the memories, a slap in the face and a push in the right direction should see me through, and obviously I don't mind if this is deleted.

Basically, I'm wondering about what I should/could use as a sealant or varnish on a picture I've (almost) painted using acrylics on canvas board. It's not the greatest work of art ever, just a design really, and there's still plenty of time for it to all go oh so horribly wrong, but it's being made for someone else, my sweetheart overseas, who I know will value it, however inferior it might look to me or any other pair of eyes. And so I know he'd be sad if bits started peeling off, flaking, if it got scratched, or if (I don't know if this can happen in practice, but it is a water based paint after all [isn't it? or am I getting confused, this late at night?]) it got wet and sticky and nasty.

So! Anything I can paint over the top to keep it as healthy as possible? And sorry to be picky, but, since I'm in the UK and most of you grrlies are in the US of A or elsewhere, I'd appreciate it if any suggestions referred to a generic type of product rather than a brandname, as brands can be rather geographically limited.* I haven't really found any shops here that sell specifically art supplies, which seems crazy, but it's true... a few craft shops, or larger department stores w/ arts and crafts supplies, and lots of drapers... but no art shops. If something as basic as wood varnish would be okay, then that would be great(I have a big ol' tin sitting in my craft chest of drawers)! If that's unsuitable for whatever reason, I'd be grateful for any other suggestions.

What a long post for a simple question. I don't talk, I ramble. Sorry... :-)

* Ms Moderator K - ages ago I started making a list of US - UK terminology that might cause confusion for those on either end of it, which I said I'd try to work out into something for the FAQ. I haven't forgotten it, and it's still ongoing, I'd have passed it on earlier, but I've been away from the internet for a while lately, and meanwhile a whole host of new posts have popped up and made it into the FAQ, many w/ examples of just the sorta thing I was talking about. So I reckon I need to catch up on that I think :-) but I'm working on it anyway...