Today's task was to service the rear brakes and sort the handbrake adjustment out as it's getting a touch high. All week I've been reading through MDTM's "how to" and getting everything prepared, this morning I started work with a skip in my step and gleam in my eye.
Then it all went wrong

Problems that I have:
1) I sheared one of the bolts off whilst trying to remove one of the heatshield retaining nuts - How easy are these to replace?
2) Having sheared off one bolt, should I give up quickly as all the other nuts look in a similar state of corrosion - and just borrow a long extension to reach the handbrakecable adjuster?
3) Having given up on the rear brakes I thought I would fit a new backbox. Regular applications of penetrating fluid over the course of a couple of hours ensured things looked ready, but all four of the nuts were seized solid and just sheared off anyway (Bit of a theme running here) - However the pipes won't shift apart so now I am completely stuck - Any ideas how to get the two apart as I really don't want to cause any damage.

The only constructive thing I managed to do today was fit a new fuel filter. Still at least it's progress :-/
Any thoughts on my issues?