https://info.caa.co.uk/eu-exit/commercial-pilots/
Q. When is the latest I could apply to transfer my licence to another EASA member state to get my licence in time for 29 March 2019?
A. "The CAA has no control over the issuance process of other EASA Member States,
we therefore recommend that you contact the proposed NAA directly on these matters.
To enable the CAA time to complete its part in the licence transfer process, the CAA advises that application forms from the NAA need to be submitted to the CAA by January 1 2019. We will endeavour to transfer any application received after this date, but the process may not be completed by 29 March 2019."
Note that it says the forms need to be
from the NAA not the applicant so that deadline is passed now.