I did a walk through here. Link.
I bought something like this when I got the Golf and it is exactly what's needed, although now you know what to look for it could be cheaper.http://www.ebay.co.uk/itm/Laser-1314-Brake-Caliper-Piston-Rewind-Tool-Kit-New-/220924246476?pt=UK_Hand_Tools_Equipment&hash=item33701c79ccLocal motor factors stock them too.