Right - I have ordered some race matrix Uberbike pads, some Shimano XT RT86 Ice-Tec rotors and some TRP compressionless cables. Will report back
Finally got round to swapping cables, discs and pads this weekend. It has made a large but not mind blowing difference so far. I guess everything still bedding in. The pull certainly feels more solid with the compressionless outers, braking seems stronger and I am not getting the sort of juddering I was.
The descent of Anerley Hill this evening (with the inevitable red lights at the station) will be the big test.
I am going to stick with this setup for now and see how it goes.