Had my car up on the ramp today, underneath theres two tubes going out/ in to the gearbox. One is fine (the one thats bolted on at the other end) but the other you can move forwards and backwards and it feels loose. I'm guessing this is not normal?

 

that's the gearselector arm, the universal joint wear and make the selector feel sloppy.
either replace of make modification to tighten the slack in the bushes.

 

Easy to replace? Easy to modify?

 

you need to renew the bushes, there should be a guide somewhere on the net.
bottom of the page:
http://www.zetecinside.com/xr2/gearbox.shtml

 

That sounds quite complicated, steel rods, cutting etc. Is there not just bushes that can be changed?