Given they're already drawing down a pension, have they not already triggered the MPAA rules so the max relief is gonna be £10k anyway?

Appreciate I'm not an expert on this specific area and there may be a carve out for inherited pensions.

Are you sure you've not overpaid tax to HMRC if you are non resident?

Fines for what?

You're also liable for the rental profits as an fyi

Yes

If you're resident in the UK at the tax point and you suffer tax overseas on the same income or gain then unilateral relief should be available as a credit against the UK tax due

The employer contribution is tax free on the individual, the annual allowance is just clawing that relief back.

Yes but what was it, as a UK dom and I assume UK tax resident (?) you're taxed on worldwide income and gains as they arise, not when you transfer them to the UK.

If UK pension it generally remains taxable here outside of exemption under treaty.

UK Denmark treaty gives the impression no exemption will apply if you were ever tax resident in the UK.

Law says you need to take reasonable care. There was a tribunal recently where the appellant used chatGPT, the advice was 'hallucinated' in parts, reasonable care deemed to not have been taken.