As I suspected. I know you say you’ve worked remotely from Sardinia, but have you thought that maybe your career is also a major factor along with environmental differences (which is definitely an issue with London due to air quality / weather alone)? Working remotely is often very different health wise than doing the same job in an office based on my anecdata experience (both working from home, but near-ish to my employer, for over a year, as well as spending a year on the road working remotely from an camper/RV).