You can do it in a virtual machine, and people frequently do. The software can't detect nor escape it.

Unrelated (seriously), there's also OARC, the online amateur radio club. It's on discord (boo, proprietary), but it's got some of the most exciting projects and a really young crowd. I'd highly recommend it.

https://www.oarc.uk/

They want someone to invigilate the exam. That is reasonable, particularly since it appears as though in-person exams are still available.

I'm not sure what the situation is in GB but, in Canada, the question bank (and answers) were publicly available from the licensing body when I took my exam. Under such circumstances, it would be trivial to cheat. (It was also quite handy. I made an online test generator for the club I belonged to so people could take practice exams to figure out when they were ready.)

What does that mean? They want to use a cheat-discouraging browser?