I'm working for an employer in London. There is an option for me to work partially from home which means also abroad (EU). I'm considering arriving in the UK on Monday in the morning and leaving on Wednesday in the evening (spending 2 nights only). In this way I might reduce my stay in the UK to less than 90 days per year.
I'm aware that for the non-resident status some additional requirements are needed. Let's assume that I meet them. Thus I would be UK non-resident working Monday till Wednesday in the UK. What would be the amount of tax and National Insurance saved in this case?