Intercalation options are here:
https://www.intercalate.co.uk/
There are some good ones. DD studied biomedical engineering, which was within Imperial's engineering department. They literally joined in with third year engineers, after a couple of pre-sessional courses in maths and electronics. Tough but rewarding and which will apparently stand her in good stead should she want to pursue an academic route. (She did not try for academic F1/F2s partly because there was nothing particular that interested her and she wanted to focus on the medical training rather than try to juggle both, but did work as a research assistant for her elective and the option remains for her to take a PhD should she want.) A friend's daughter similarly studied tropical medicine at the London School of Hygiene and Tropical Medicine and used it as a springboard for a really interesting career.
That said one friend did emergency medicine from which the main learning was that they did NOT want to work in A&E. A useful lesson perhaps.
Intercalation is expensive and does not offer immediate short term advantage, though DD is told that hers will look good on her CV at later stages in her career. (And a poor radiologist regretted asking his placement students if they knew how a scanner worked only to have DD go into a deep dive about algorithms.) Worth doing if you are fairly sure which direction you would like to go in.
DD did pretty well on her SJT, despite being dyslexic, so would have had a good choice, but by then she had decided to side step the process by picking somewhere completely different. She might well return to London later in her career, but short term she is looking forward to days off in glorious countryside, and a good pick of placements. (Going somewhere less popular with relatively high points gives you more priority, though each area does it differently.)
I understand that the F1/F2 process changes again next year. SJT is not kind to students who have English as a second language or who do not speak English at home.