Thanks everyone for your help. All done with a slip coupling, and a bit of cursing. Had to cut some of th boxing away to get enough elbow room. I ended up leaving about a 10mm gap where the slip coupling goes over to allow enough room, but thats my expansion gap! 
But no leaks now.
I hope the perfectionist in me will carry me in good stead. I also tend to over engineer things, but at least I know it isn't going to fall down.
But no leaks now.
I hope the perfectionist in me will carry me in good stead. I also tend to over engineer things, but at least I know it isn't going to fall down.
