Just to finish off this thread.....
Rear brakes were a total nightmare!!!
I got one side caliper bolts off after battling for ages. Used a 19mm ring spanner attached to a 'socket to spanner converter's attached to the triple square bit. Had to lie down and push spanner with my foot.
Other side just wouldn't budge. Tried everything. Ended up abandoning and purchasing a Sealey AK6682 Flexi-Head Ratchet Wrench 1/2"Sq Drive Extendable for £30. Made the job about a thousand times easier. Still a bit of a fiddle to get the triple square into the bolt, but managed it. After that it was plain sailing (apart from rounding off the set screw holding the disc onto the hub).
All in, having sourced genuine parts, bought the tools, I still came in under what a garage would charge, and have the satisfaction knowing I did it.
Side note - I forgot to remove the coat hanger I used to hold the caliper.....had a service the other day where they found it - I pleaded ignorance.