There's nothing wrong with grey imports per se, It'll be made in the same factory, by the same people, the only difference is that it's not imported by the official UK distributor. But this does have implications in terms of warranty and support. A £200-300 saving would be definitely worth going for, £100 os so... well it's borderline really. Don't get me wrong, I don't have any particular loyalty to any UK company at all, (they're all just after your cash), but you do need to consider some of the issues.
Is that £110 saving still there if you pay customs duty, VAT and the carriers handling charge?
If not, and it's effectively evading duty, then I'd be very wary of taking it out of the country again, Customs aren't daft and if you can't prove duty has been paid you're in trouble. Unlikely but not impossible.
What happens if it turns out to be a lemon and needs fixing, can you get this done under warranty easily?
Again, more than likely it will be fine and you just won't need any warranty support at all. But it's not unknown to get an absolute dog, and you can't half get the run around if the supplier is at the other end of the world.
No I don't usually look on the black side of everything

and to be honest only you can decide if it's worth it. But do be realistic and consider the options.
cheers