Fallen:
Now, you have the choice to buy copies from UP at a reduced rate(which I'm not keen on) or they'll print them anyway even if you don't buy a copy (but, yep, you get no royalties). Books go on sale over the UK and beyond (so they say) etc, etc..
If I'm reading this correctly, your choices are:
1. buy a copy at the "reduced" rate (you don't mention what the price is, but I'd be surprised if you have much change from a tenner); or
2. don't buy a copy and don't receive any royalties.
Neither option seems particularly attractive to me but at least option (2) just means you don't make or lose any money, while option (1) means parting with cash.
Unfortunately, there isn't much of a market in the UK for poetry collections and few book stores stock collections from unkown poets, so I'd be surprised if United Press have any kind of distribution in place for these collections. In fact, given that they offer a self-publishing arm that solely seems to rely on authors buying and selling their own books (
link here for anyone interested, I'll go out on a limb and say that the chances of them having any kind of distribution for placement of books in stores is slim.
If you're interested in publishing poetry, then magazines and poetry slam events are probably the best route to go down.
If you're still able to withdraw your poems from publication then I'd do that in the first instance. If not, then check out your contract for when the rights revert to you and chalk this one down to experience.
MM