Cack handed attempt at bleeding my rear brake, overtightened the bleed nipple and mullered the thread. Mineral oil everywhere. More upset that I couldn't ride it today. Hope the new calliper arrives before my day off on Thursday..

I should learn to be less heavy handed.

It's too late now if you've already ordered a replacement, but assuming your caliper has a standard M6x1 thread, you should have been able to helicoil it, or tap it out for a slightly larger M7x1 bleed screw.
I've never tried either option myself, so can't promise it would work, but if it was my caliper, I'd certainly give it a go.

The classic QR/bolt issue:

...been treating my Speedfox really bad, well good actually - riding through mud and snow-mud-mess and other goop. But then I left it, no cleaning, greasing what so ever. Just the next abuse. After more then a month, I did give it some love and new tires. When I set out with the clean smooth running bike it was squeeking like a dozen pigs on fire. I "knew" it was the bearing of the rear suspension until I checked the tension of the DT RWS thru bolt...
Thank god I was only leisurely cycling along to visit some friends.
After tensioning it correctly, the frame doesn't seem to need new bearings...

Thanks Graham - the caliper was only £20 (deore M446) so I figured it would be less hassle to buy new....