Both extruders can't be used - broken

[Billzilla]

I have ongoing problems with the nozzles jamming and yesterday the LH one stopped printing again ...... click, click, click ..... I normally don't use the RH one so I removed the nozzle to stop it from dragging across the prints.
Anyway when I tried to remove the LH nozzle it just broke and so has left most of the threaded part in the heater block. So since I wanted to print something I decided to just swap over to the RH unit. All good, until I found that the heater block wobbles around on the steel tube it's attached to. The tube is in tight into the alloy block that holds it - so tight that with the locked screw would out (see empty hole in the photo) it still doesn't want to move - but the heater block is obviously not tight.
The way the whole thing is designed is pretty crappy, there's no way to take the wires off the heaters easily that I can see and I don't know how I'm going to replace the LH one. It's easy on the UP as there's a short bit of wiring then a plug you can undo.

Any ideas how I can change the LH heater block and also tighten up the RH one?