Aaaaaaahhhhh so annoyed!! It would appear that the thread is knackered on the mech hanger :/ I don't have a tap to hand either......Also, the springs inside the mech are knackered....Both the main de-railer spring and also the cage spring.......So.......I need a new mech, and need to look at either tapping the hanger or finding different way of hanging the mech.....Of course I could turn it into a single speed...... ????

Any suggestions? :D

Update!

After some jiggery I've sorted both springs - I assumed they had lost tension but the main spring problem was with the cage not tensioning the chain properly. Upon closer inspection the stop in the cage has worn away the soft alloy of the main body and turned round a revolution. A little bit of inspired bending has sorted that out....So...to the hanger....Tap it? or....Just get it heli-coiled...?

Couple of pics then I really need to tidy the workshop!!!

Steel Hanger

Alloy stud

Never trust a guy with a tidy workshop