Hans,
I think it is OK to send seeds to the UK in 2022, the new rules are not expected to start till 2023.
This is what the seed exchange page on the SRGC site says about seed donations from EU countries:
From EU members: our current understanding is that implementation of these rules for seed from the EU has been delayed until 2023, and so donations from the EU will not require phytosanitary certificates this autumn, and you will be able to donate as normal.
So I think you can swap seeds with members in the UK this year.