So latest here is... I managed to borrow a wrench from a neighbour and now have fitted all the pads/discs to the necessary settings.
The main annoyance was the b***ard trox bolt that refused to come out but after buying the appropriate female E socket it worked just fine (note, I've seen a few people say it works just fine with a standard hex socket, it doesnt, at least if they were as stuck on as mine were!).
I pumped the break a few times (5-10 times) before a quick test drive.
So far it works... but one thing struck me that you have to press quite 'far' on the brake pedal before the full brakes engage. When doing that they seem to stop just fine, but I would have expected (after two new rear pads/discs were fitted) that they'd be a bit more responsive that that.
Does anyone know what could cause this effect, and whether this might be something that will get better with time with new brakes, or something I should be worried about?