Another silly flat mount post mount adapter question

chrismcgt1d2fHuT983

Hello all. So, I've got a post mount fork for a frame build I'm currently planning. Unfortunately, I can only get hold of a flat mount caliper for the levers I'm using. I'm aware of the adapters that AS Solutions make, but before I pay £27 to get it shipped to the UK I was wondering if anyone knows anywhere I can find one at a more reasonable price?
I appreciate it's a niche part, just figured I'd ask before I go after international ordering! Many thanks

i.bhamra

Merlin have TRP and Shimano versions for £10-£15.