So here in Australia, labour costs are pretty high - was planning to get my alternator tested and rebuilt, and most were charging a big assessment fee jsut to look at the thing.
Bought an aftermarket unit on Ebay and it took the seller a week to tell me it was out of stock, so got a refund and bought a Bosch unit 0 124 515 042, which was a direct replacement for the alternator alrady in the car.
Changed it over this evening - I can do the job in well under an hour now with my eyes shut!
No improvement. Still low idle, stalling.
Since I've already narrowed it down to an electrical problem (car runs perfectly with alternator disconnected and everything else connected as usual) the next step is to trace back connections from the alternator. Will remove the Y cable which I installed a couple of years ago to make sure it looks good still,
I might even replace the starter motor while I'm in there - I'm pretty sure I bought a replacement starter when there was a huge ebay sale a while ago!
Thankfully with winter setting in, I'm not missing driving the car anyway - it hasn't been convertible weather for ages. But I want it fixed before spring 2021!