The pads look fine I think – so is it a case of getting a brake winder from euro car parts and winding it back in. Then out again to free it up?
I did mine with the peg-spanner thing you use for changing discs on an angle grinder, worked perfectly.
Mine’s a bit older than yours, 2013 Transit, I don’t know how similar the brakes are but on mine the handbrake cable goes into some sort of arm on it, looks a bit like a cable disc caliper on a bike, and there’s a spring to return it. One spring had gone on mine so the handbrake was a bit rubbish, and a pad was rubbing, a bit like yours, almost through to the backing!
Compatible, new, caliper off eBay was about £40. I’d never changed one on a motor vehicle before but it was surprisingly straightforward, apart from some rusty bolts which were an effort, 8years difference might make yours a lot easier! Bleeding was a doddle too, if you can do bike ones you can do van ones. A chap on YouTube showed me how to do it, gave me a lot of confidence.
Stating the obvious maybe, but if you fit new pads do both sides.
Beaten to it by RNP. He’s better than me, I’m at best a 6, despite the recent snapped glow-plug incident, and even I managed fine.