My post-lockdown commute back to work

[OhOh]

QUOTE=Mendip;4194622]Due to Brexit from 1 January 2021, you will need a Residence Permit to work in Norway. Entry to Norway will be refused without a Permit.
To get a permit, you will need to have the appropriate qualifications and also be paid a market rate.

What we know so far is explained on our website and at the Norwegian immigration service.[/QUOTE]

But your in Sweden, yes?

Your accounts have sent you a Norway specific requirement.

I would suggest you inspect your contract.

Speak to your boss either:

1. Double shifts to complete you currently programed tasks prior to Dec. 31st. At an enhanced rate
2. As your work appears to be computer based and meetings, arrange a suitable secure connection and perform your work and attend meetings remotely, from the UK. Again rate enhanced, to cover any UK taxes to cover the unforeseen plus setup/fees. To work within any yet to be announced let alone legislated, Swedish modified requirements

They have seen your work abilities which they have deemed acceptable. If Sweden goes into lock-down and remote working becomes mandatory, where you sit is irrelevant. Your record on delivery is proven.