Ok, thanks. It’s the catch on my 2/3 seat that’s broken, the 1/3 seat back still works – so I can tilt the 1/3 seat forward to see how the catch (that fixes the seat to the car) works.
It’s just v difficult trying to release it from sitting in the boot with a piece of coat-hanger-wire and a screwdriver, but I’ll give it another go tonight – sitting in my boot with a screwdriver.