Too busy trying to finish the room to complete this thread before, but here goes.
The gloop set up. Not sure if the loose tongues are in the picture, but they were cut from 4mm ply and used in all the end groove/side groove connections.
More laying - can't remember exactly but the field took about 4 days I think.
The border took about the same 4 days or so (surprised me) what with all the cutting, grooving, fiddling around getting lengths balanced around the centres of the runs, corner mitres and so on. Used a tracksaw to trim the field straight, then ran a router with a bearing guided groover around the edge to give a t&g joint between field and the border of two soldier courses. Went for a 50/50 offset on the soldier course because it looked best when things get tricky ie short bits of border where you can see both ends in an eyeful - bit like tiling those look far easier to the eye if they are based around a whole piece centralised in the run, with identical length shorter bits at the ends to marry up to the required length of border. Probably something where a picture would speak a thousand words but I'm not sure if captured below. I left a 15mm gap to the wall (filled before the skirting went on with foam backer rod). Cut under all the architraves door frames etc enough to lay the blocks under 10mm and leave the same gap.
Then, sanded - hired the big Bona belt sander and did 40G and 60G, each grit lengthways and crossways (plus Bona edger, same).
Then Lagler Trio 60G. My weekend hire ran out before I finished.
Had to hire the Trio for a second weekend to do 80G and 120G . Then ETS150/3 120G on my knees just because it looked better for it.
Then 2 coats of Pallmann Magic Oil 2K, troweled on, buffed off with a Bona buffer and red/white pads. The second lot of sanding and finishing took a long (ie 3 day) weekend.
I would say never again (and my other half has been more definite still) but I have nearly enough in the shed to do our bedroom with a different border or something...