LASER do a 36mm 1/2" BiHex Deep impact socket for about £9.00
it should be available from most decent Motofactors
its what i used on mine.
you should have a set of inpact sockets 10mm-19mm (the inpact sockets are better quality and will outlast cheap ChromeVandalum ones) they also usually come on a rail or in a steel carry cage, so you are less likely to lose one.
for Renaults you will also need a deep 16mm for things like seats.
the caliper bolts should be either 15 or 17mm bolts.
you also need the laser caliper windback tool (ref number 1314) with the correct renault head attachment (7 i think?)
once you have wound the piston back, put some copperslip in the two holes on its face(fill them in fully), to prevent later corrosion of the holes.
if the attachment wont fit in the holes correctly, check for fitting(does the tool actualy fit correctly) and is there any corrosion in them? scrape it out or get the tool changed.
I sheared the locking pins out of an attachment tool due to it not fitting smoothly in the Piston face. Laser sent a new part out free of charge.