Thank you to everyone who contributed to this thread. You've been very generous with your knowledge and advice. Just a quick update. Rather embarrassingly, I found a "spare" Goldring 1042 I'd forgotten all about sitting on the odds-and-sods shelf. As it was getting the 1042 off the Gyro that worried me rather more than fitting it to the Technics headshell, this was a bit of a godsend.
Anyway, to cut the waffle, I've collected the 1200G and installed it this morning, including fitting the Goldring. The stylus on the "found" cartridge was shot, so I've swapped it with the one that was on the Gyro.
I'm rather happy. Everything sounds very good indeed. I'm just listening to the old DG Geza Anda version of Mozart's piano concerto n°21, K467. It's fluid, has drive and the strings don't bite or set your teeth on edge. Detail is very good, too. Dire Straits' "Telegraph Road" was a great listen as well.
I value all the advice on cartridges. I'm very likely in the next few months to buy another headshell and maybe one of the MC cartridge recommendations you've made; perhaps the AT33PTG/II.
One last question. Has anyone dealt with Juno Records ? They've got a replacement stylus for the Goldring 1042 at under £170, which is £50 cheaper than the best price I've seen elsewhere, and £70 cheaper than the typical price.
https://www.juno.co.uk/products/goldring-d42-replacement-stylus-for-1042-cartridge/661186-01/
It seems rather tood good to be true.