there was a thread on this not more than a week ago Dan.
The consensus was to save yourself the hassel of using a vice etc, and just buy the specified tool for the job. Meant to pick one up from Halfords myself too in expectation.
well I finished last night, I thought it was only going to take me an hour, but I didnt have a 7mm allen key so for the front I had to take calipers off, and the rear I didnt have a tool to screw the piston back, so I used welders clamps and some grips, it was hard tryin not to catch the rubber boot, thank god its over cheers guys