From the email i received from coinbase
If the United Kingdom leaves the European Union on 31 October 2019 without any withdrawal agreement in place, it is expected that CB Payments, Ltd. will no longer be able to provide you with E-Money Services, such as your Euro wallet.
In light of this, we plan to transfer your current relationship with CB Payments, Ltd. to another licensed Coinbase entity within the EU. The Coinbase Services you receive will not be affected by any transfer.
Due to the ongoing uncertainty around Brexit, the timing of any transfer is still to be finalised and we will be in touch closer to the time with further information.