Hi folks.
Had some wheels off yesterday to examine the brakes, and after nearly 37k, the original pads are ready to be changed. As many others have said, the rears are worse than the fronts. The new (genuine) pads are on their way, but looking at previous threads I appear to need a piston winding in tool for the rear calipers.
Could anyone who has already done this please let me know what they actually used. I am wondering if I have got to buy/scrounge a special tool from somewhere, or whether something else can be used instead.
Cheers.

I just used a standard woodworking "F" clamp and a couple of bits of wood put a bit of wood on the piston and a bit on the back of the calliper slip the clamp on and tighten it slowly to push the cylinder back in the only special tool you need is the allen key which I think from memory is 7mm so not a standard size but readily available from a motor spares place as a 3/8 socket drive .

An update to my original question. Even when the pads arrived, there were instructions in the rear pad kit which clearly showed the need for the winding in tool. However, I took a rear caliper off anyway, and hey presto, it is a traditional piston that doesn't need winding back! Result, a complete new set of pads fitted in no time- it took longer to jack the old girl up and remove the wheels than it did to change the pads-dead easy