An update...and a big thank you to Doug for some great advice!
My flywheel side race above, the one with the step/lip, is actually a push-out one from the throw out cam; it also has a large crack across it. As I was short of one flywheel side race, and having read on this Forum about the success of converting the ball bearing trust race to a scintered (Oilite) bronze one, I bought the parts and set to work.
Sourcing the parts was surprisingly easy. The Oilite washer is a Bowman one (part number AW 32 48 04) and was supplied by BearingBoys in the UK, and as I wanted this washer to run against hardened, steel surfaces, I bought 1mm thick and 4.75mm thick needle roller bearing raceways from SimplyBearings also in the UK --- I wasn't sure how many of these 1mm raceways I'd need, but at £4/each, I bough a few spares....
The Oilite washer only needed to have its I/D opened up, so there was no issue with closing up the pores on the bearing surfaces. For the 1.mm raceways, the OD needed to be reduced which I just managed to do on my rather ancient Sheldon lathe --- fast chuck speed, no cutting fluid and carbide indexed tool:
And so to the throw out cam. I could have left the Oilite washer running against the old roller race but as I had a throw out cam with a removable race, I decided to do the job right and make a new flat bearing surface from my 4.5mm thick hardened needle roller raceway. This entailed cutting a 2.75mm step in this washer for the interference fit into the throw out cam. i.e it would leave a 1.75mm thick surface on the top of the throw out cam. Cutting 2.75mm doesn't sound much but it took several hours and multiple carbide tips to get through this hardened raceway --- with quite spectacular sparks and molten swarf, so wear eye protection!
And this is what I've finished up with. I needed 2mm (2 x 1mm washers) on the flywheel side to ensure the top of my 1/4" thick Oilite washer cleared the main bearing hub. I could have ordered a thicker Oilite washer but that would have been a "special order" and I just wanted to get on with it...
Having installed the clutch several times to check clearances / adjustments etc, that helped me decide on the finally thickness (1.75mm) of the new raceway in the throw out cam.
So, it works on the bench, but will it work when the engine is running? Time will tell as I'm not quite ready to attempt an engine starts...
Thanks for all your advice Doug!