As you can imagine, Popple, I'm sure there are some. I've fitted both types many times. We usually have to go with what we're given.
Altering the plumbing is the usual way. If you can't do that for some reason, maybe use a long flexible connector...............
http://www.screwfix.com/p/hydraquip-chrome-push-fit-hose-15-x-500-x-13mm-x/35102
It might be difficult to make it look acceptable though.
As for the outlet, most WC pans have a "straight out" spigot. Just use a 90 degree pan connector...........
http://www.screwfix.com/search.do?fh_search=pan+connector&fh_view_size=20
There are loads of them, even flexible ones.