I need to change the rear brake pads on my 53 plate Octavia, i have removed the brake pad housing which also houses the brake caliper. Once i have fitted the new pads i am unable to push/retract the brake caliper back into the house to refit over the new pads.

is there a method or technic to push/retract the caliper (or is there a special tool required to do the job?

You need a winback tool to screw the piston back in. It doesnt just push in, like most front calipers do.

http://www.vwspares.co.uk/product_info.php?products_id=1450

Something like that

If you have a large pair of 'gas pliers' then it can be done without the tool, but you need to put pressure on the piston at the same time as winding them back in, so an extra pair of hands would be useful .... or get the correct tool as it makes the job MUCH easier

I need to change the rear brake pads on my 53 plate Octavia, i have removed the brake pad housing which also houses the brake caliper. Once i have fitted the new pads i am unable to push/retract the brake caliper back into the house to refit over the new pads.

is there a method or technic to push/retract the caliper (or is there a special tool required to do the job?

As stated, you need a wind back tool. Do not attempt to just press back the piston or use a vice without turning piston, you will damage it.

This job can be done as metioned without a windback tool using various pressing clamps and also turning with circlip pliers or similar, but forget it that is dam hard work and knuckle cutting. Especially if you have not done it before. Stick with the correct tools for the job like this this one.

Some angle grinder keys fit the cut outs in the piston perfectly, used in conjunction with a G clamp it'll do the job, but it is a bit of a fiddle as said, but if the shops are shut and the car in bits it can be done in a few minutes.