In the end I went with the tiagra derailleur and an 11-32 cassette I had. I got some tiagra 4720 hydro levers off ebay so have retained hydraulic brakes… delighted. Bar end shifter for the FD retaining the triple crankset. Ritchey beacon bar and a Brooks cambium saddle I picked up off Facebook marketplace to finish it off.
Only had a wee spin around the garden but pretty happy overall.
Brakes need a wee bit of fettling before I take it any further. I always struggle to get hydraulic brakes well set up. They’ll probably get looked at by LBS.
Still waiting for carbon fork to arrive but no even sure if I want it now.