I just thought I'd mention here that Olympia flatwounds are on ebay for £12.99, but I just made an offer of £10, just to see, and it was automatically accepted, I don't really need them but they'll get used.  So if you want to try flats on the cheap then see how low an offer you can get away with, or just offer a tenner and they're yours. 😎 https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F332486029353