I replaced the head, as it was damaged by a previous "repairer" dropping a nut into the intake. This destroyed the piston and messed the head up badly. I was able to make the head functional while looking for a suitable replacement, but I suspected that the sticking valve was the original reason the head was removed before it got damaged.

After 7 months of looking, an 8k mile Disco Sport head came up, so I bought it and fitted that instead.

I've got the damaged head under my workshop bench, as I'm not sure what to do with it yet. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Mikeben wrote:

This might take me some time to get round to. I'll send some updates as I go. Thank you to everyone for your help so far, I really appreciate it