All boats on inland waterways managed by the Environment Agency are required to be registered. PTRC registers all club boats that row on EA waters, but private boat owners are responsible for registering their own boat. 
British Rowing offers reduced price licences for non-EA water clubs (like PTRC). Members who wish to take their boat to EA water can pay PTRC for their registration, and PTRC will register their boat with the EA at the reduced price.