The following reporting apps all have publically available maps that can be viewed to see where mink are present;
INNS Mapper - https://innsmapper.org/home
iRecord - https://irecord.org.uk/all-records (Login required)
The NBN altas ultimately holds all the biodiversity data for the UK and currently holds over 385 million records from 180 partners;
NBN Atlas - https://species.nbnatlas.org/species/NHMSYS0020774297
NBN Atlas (Interactive Map) - https://records.nbnatlas.org/occurrences/search?q=lsid:NHMSYS0020774297&fq=occurrence_status:present#tab_mapView
iRecord - https://irecord.org.uk/all-records (Login required)