I live close to Southampton and I know they are not favoured here by drivers. like anything that's leased you can hand it back but the penalty payments make that highly unattractive.
Bus companies shuffle buses around between garages (often hundreds of miles apart) when they loose contracts and sell or scrap the oldest they have or even delicense them and store them
to save money, but Freightliners fleets is quite modern in real terms so that's not really an option other than to ship more 66's to Europe is demand picks up