Good luck with that, and i do mean it.
Currently the UK is doing quite a bit to antagonize the EU where it can, so good will from the EU, and it would require good will, is probably in quite short supply. Not to mention, that currently many business areas are hurting under the new rules and all are lobbying for change.
There was ample warning about the loss of EASA license privileges, i believe EASA published their first advice in 2017 for a possible hard brexit. Which did happen for services now. And that was clear from the negotiation direction of the UK since around a year ago, which is while some UK companies actively switched their pilots (and Flight Attendants) licenses to european in preparation for that, like the orange bunch for example did. Including some UK based trainers from what i hear, as it was quite clear from the UK CAA pretty early on that it would accept a conversion from EASA to UK licenses in the beginning.