The patent twat profession is extremely London-focused, for one. Obviously jobs exist elsewhere, but landing a job that’s in your technical area AND for your level of experience AND where you know they’re not all cunts is hard enough if you also want to work in a particular not-London location.
For private practice, anyway. The in-house roles are clustered in Oxbridgey tech-heavy places or spread out on industrial estates in places like Teesside.