Hi Mike
Sorry for the slow reply, I had to check my stock and get some pictures.
You are correct, the CSL progressive rears are now NLA too. I have just recently made rear springs replicating original new CSL rears (but slightly lowered) as them not being available was causing me an issue with restorations. I have tried and tested one set of those and appears to be good. The picture of the Tiaga CSi is running with my fronts and the smallest 28 mm rubber (1 dot) so it could be raised by 10 mm by using the 38mm (3 dot rubbers) if this is a little low for you.
If this is of interest to you, let me know and I'll PM you the prices.
I currently only have 1 set of rears in stock as I didn't want to order too many in case I wasn't happy with them, if I order more, they will be 6-8 weeks to manufacture. Fronts I have more.
Paul