Split working between Zurich and UK home?

Hello,

I’m hoping to find someone with first-hand experience of the following arrangement, particularly post-Brexit.

I’m a British national currently based in the UK. I’ve been offered a senior role at a Zurich headquartered company on a Swiss employment contract. Rather than full relocation, the preferred arrangement would be to spend 2–3 days per week physically in Zurich and work the remaining days remotely from my home in the UK, where my family lives.

I understand the broad framework, B permit tied to the Swiss employer, Swiss withholding tax on days worked in Switzerland, UK self-assessment for global income with Swiss tax credited against UK liability, but I’m keen to hear from anyone who has actually structured this arrangement in practice, ideally post-2021.

Some specific questions I’m trying to get clarity on:

1.    Did your Swiss employer formally agree to UK remote working days, and was there a written policy or addendum to your contract covering this?

2.    Was there a maximum number of UK days stipulated, either by your employer or advised by a tax/immigration specialist?

3.    Does your employer face any Swiss social security or compliance exposure from you working days in the UK?

4.    Did you engage a specialist (EY, KPMG, or similar) and if so, what was the most important advice they gave you?

5.    How has it worked in practice, any issues with the cantonal tax office, HMRC, or permit renewals?

Any experience, even partial or indirect, would be genuinely appreciated. Thank you