No real knowledge of the actual spec but just a few thoughts on the description you have given.
Install section:-
Generally no problems there.
I am worried about the brown tape mention, I hope it was sleeving as you have said at all other points, tape would not be appropriate.
The wiring is correctly organised.
Ring Final
Sounds correct, when you say through to spur I assume you mean from first socket to fused spur and looped out again to the last socket, which is right.
Bonding
All sounds OK I assume the bonding clamps had the safety electrical….. labels on them and the clamps were firmly attached to the pipes and the bonding cables securely fixed to the clamps.
Fb 200
One I do not know: do you need to use fire resistant metal clips for the p clips and did you do so?
Other than that all OK.
3 phase and neutral isolator.
I would describe the cable from the banjo to the earth as an earth fly lead, do not use the word bonding in relation to this cable. Preferentially this cable would be a single core insulated cable. Does the isolator not have a neutral terminal to loop the neutral through, I am surprised you have to use a wago, though if there was no neutral terminal then this is fine.
3 phase dol starter
All sounds OK so long as you used the correct SY gland and not a compression gland.
Good luck with the heating, data and Inspection, testing, faults tomorrow