It seems that, if you hold a licence now ith the UK as SOLI, then if you take no action this will become a UK only licence at the end of this year. As some say above there is nothing that says that after this year EASA will treat this as anything other than a third party ICAO licence and, if you wanted an EASA licence after that date you would have to retake all the ATPLs and take an ATPL skill test just like an FAA licence holder would. On the other hand, if you transfer your SOLI now to another EASA State your EASA licence will be maintained and the UK CAA say they will then issue you a UK ATPL on an equivalent basis.