Where were surrendered U-boats used as targets?

Where were Coastal Command practicing attacking surrendered U-boats in late 1945 and possibly early 1946? Also which units were involved?

The Grey Wolves Of Eriboll says thirty of the Operation Deadlight U-Boats were allocated to the FAA and Coastal Command as practice targets. The 3rd Submarine Flotilla was allowed to use others as targets (the British submarines were painted yellow and red to distinguish them). Seven were disposed in this was by HMS TANTIVY. The final group of three U-Boats left Loch Ryan 8 December 1945.

With the name of the operation it was easy to find more info. It seems most of the U-boats were scuttled or sunk by ship/aircraft fire near the North Atlantic ledge north west of Ireland.
From the aircraft perspective rockets fired by FAA Fireflies of 816 Sqn and 254 Sqn Mosquitos sunk some whilst bombing and depth charges from 179 Sqns Wellingtons and 201 Sqns Sunderland's sunk a few more. Probably the last time Coastal Command had a crack at any submarine with live depth charges? They did carry out "Buckjumper" missions on friendly submarines but this was only with practice bombs.

There are a few pictures in the British Newspaper Archive.

Not relevant to this but found these

Great Britain Ministry of Information: Daily Press Notices and Bulletins:1941-01-14

at University of Texas Libraries, The University of Texas at Austin

I have seen the maps there previously but there seems a lot more.