If a person earns £80k outside London, what might be the equivalent salary in Zurich to roughly match the living expense ratio?

Would it be fair to assume the multiplier needs to be at around x1.4, i.e. 40% more, i.e. £80k*1.4=£112k = ±140k CHF

thanks for your insight!

I would always check Numbeo.com
It gives you a fair idea.
When I moved over from the UK, the Cost Of Living was a big surprise even with a decent increase but then you figure out how to make things work and how to find the bargains.