172 Cup poor handbrake performance

The car has recently passed its MOT so the brakes are working fine but the handbrake is really poor. It’s been adjusted a couple of times but I need to pull up the handle as far as it can go to stop it rolling on a hill. Can anything be done apart from a refurb of the calipers? Maybe new cables?

There's quite a lot of adjustment available on the adjuster rod so I'd look at adjusting that a bit more

Also worth looking at the handbrake levers on the calipers, I had it on mine that although the levers were moving as they should, the piston in the caliper wasn't moving enough so fitted a new set of calipers & had to loosen the cables a lot after that

Check the pads are fitted correctly, as in the tab is piston side, adjustment is a pain in the hole due to terrible location of adjuster above exhaust

Could be stretched cables, my handbrake ended up being like that so replaced both cables and was fine afterwards.

It could be your handbrake cables are old and have stretched which has been mentioned.
I was experiencing the same. It just wasn't holding very well on steep hills. I always leave it in gear anyway but obviously wanted the handbrake to hold the car.
My cables are only a couple of years old so ruled them out.
I rebuilt the rear calipers and they're now holding the car as they should.

For new handbrake cables you can pick them up from here.