Trouble resetting caliper piston!?

[Frameboy]

Hi guys,

I've done a ton of research into this before attempting it my first time. My B5 needs new pads all round and discs on the back too. The garage wants 300 quid for the job and I figured I could save myself a bit of cash. Felt pretty confident and got all the tools and stuff together for a third of that.

Took apart the caliper and removed the old pads, used a clamp in the old back pad and tried to push it in as instructed on all the videos I saw, but I can't get the swine to retract all the way in to make room for the new pads.

Any suggestions? Going to borrow a heftier clamp later and take the cap off the brake fluid pot.

Cheers!