@TimBull Hi buddy! This is wonderful passion, Tim and I understand you very well. I also love castles and sometimes I can add new old castle to Google Map like this few days ago in the Roundhay Park. You can add to your list if you want.
Roundhay Castle is located in the northern part of the park, between the lakes: Upper and Waterloo, Roundhay Park, Leeds LS8 2HH.