Good points N_a_B.
This is the Government position on the disposal
UK Nuclear Submarine disposal
UK Nuclear Submarine storage at Rosyth
This article also backs up your thoughts about the dismantling likely to be done on site. Navy Lookout RN Submarine Dismantling
Your observation about the difficulty of towing a submarine appear to be correct which is why they fit reusable tow bridles to decommissioned US Navy submarines when they are to be moved.
Decommissioned USS Baton Rouge fitted with a reusable tow bridle around the bow.
Last edited by Going Boeing; 20th Feb 2022 at 05:07.