So far, before taking the plunge, I think this is as good (value) as it gets.

Cassette – 11-36 from on-one.
Rear mech, SLX cluth from Merlin (although price has sqeeked up and only in long cage now)
Chainring – works components (bit of a lead time and superstar are possibly coming up with something similar soon, undoubtedly cheaper but as good?)
Chain – not looked into that yet but they apear same’ish everywhere.
Rear shifter – stuck on that, pssibly Zee from CRC.

Any other bargains spotted, or anything to sell gladly considered?

I just got delivery yesterday of mech GS SLX £45 and SLX shifter £15 from bike discount in Germany.

I have just got a load of stuff from Merlin, minimal price difference when comparing all over the place with Merlin being a few £ out of £80 more than placing a whole heap of individual orders. I went with them as it would mean one package. Wiggle were a close second on the price, CRC were noticeably more for some bits.