My gran was an Irish country girl from Cavan who went down to Dublin and then emigrated over to London to train as a nurse. This was in the 1920s', I believe after 1923. Gran told me she took "elocution' lessons to refine her Irish accent as in those days it was not particularly helpful to have an Irish brogue.
Is there any record of Irish people entering England at that time? At that time she would have been coming from the "Irish Free State" on a ferry boat. Were they even documenting emigrants from Ireland at that time?