After some dicking around working out the best thing to do, I ended up scooting off to B&Q to pick up a section of pipe and a jubilee clip. Got back and fixed that - I'll have to call the plumber on Monday to replace the thankfully short but unfortunately bent piece of 22mm pipe.
I'm definitely worn out now; I've just finished clearing up downstairs, so now I think I'm going to have a shower and relax for the rest of the evening.
Thanks guys, I owe you pints/meal etc. We'll have to work out how you can collect at a later date :)
But all in all, I'm feeling a lot more upbeat about getting it all done in time, which is the main thing.