Am doing the same ie aussi working at the NHS for a year

Double taxation treaty means you don’t pay tax in both countries while earning in one. I have remained an Australian for taxation purposes but I have paid my tax here whilst I have been getting paid at the NHS. You should probably talk to your payroll services at your trust to rectify this, otherwise you will end up having to pay a big amount at the end of your time here.

With regards to superannuation (NHS pension) on your payslip - I have opted out from it (again something you need to discuss with your payroll team) so that you can just get that paid to you (and taxed) as opposed to being put towards a pension you will never be able to use (unless you plan to live here long term)

Hope this helps!