Despite the contentions of the UK Home Office, it is not illegal to arrive in the United Kingdom to seek asylum, whether by dinghy or otherwise. This is a matter of International Law and has nothing to do with the European Union. It will not change after Brexit.
It is sometimes overlooked that a recognised refugee in one European country does not require a visa to visit another European country. ‘Visit’ means a stay of three months or less. This is governed by the 1959 European Agreement on the Abolition of Visas for Refugees. (Presumably, a visa officer could refuse leave to land if not satisfied that the refugee would leave within three months.) Ireland and the UK signed that agreement many years prior to their accession to the EU and presumably the UK does not intend to withdraw from it.
Gerry can assist you in all areas of Irish Immigration - applications for Visas or Long Term Residency, Regularing Legal Status, and Citizenship, and those seeking Work Visas or Immigrant Investors.