What a co-incidence, I changed the rear discs on my Series 2 1600HF just before Christmas - I hadn't intended to as I was just planning to make the handbrake work properly, but one of the discs was cracked.
I bought a pair of EBC discs direct from EBC - £142 for discs including a pair of rear pad sets, free delivery - they look good and fitted properly. I have used EBC discs before on my Lotus Elise and they were fine. They were also cheaper than Omicron.
I bought the handbrake shoes from Omicron (exchange), I didn't bother with their spring and fitting kit as mine were ok.
I haven't taken the car out yet, but all seems to be working fine - including the handbrake (at last)!
Steve