If anyone genuinely thinks along those lines, they will be crucified by the Operations/Fleet and Planning departments. Bournemouth West CS (as was/still is) is the ONLY location that has a small degree of spare stabling space, which will often be used for various schemes, unit modifications, repaints, exam turnovers, etc.
In that regard it is currently being used for 458/4 storage on a temporary basis, but once they are gone, there will be a need for that space for other initiatives the SW has in the pipeline going forward.
If anyone thinks any given maintenance stabling point/depot can be filled with stock to its maximum physical capacity each night, and then expect the train service provision to start as planned the following day without problem , they are living in fantasy land, end of!
As I alluded to above about Farnham, certain sidings have to be kept clear each night to allow units to gain access to the CET point every night.
So anyone who thinks such locations should be stabled up to their maximum each night, I will say, be prepared for the WC's on trains the next day to be locked out of use on a daily basis, unit failure rates to increase, etc.
I can (but won't on here) quote the number of cars that a lesser experienced project Manager quoted me as being 'do-able' in relation to Wimbledon depot (both parts) many years in the past. Taking every siding in to account, they were correct, if one is talking about purely stabling and nothing ever moves.
Coming from an operational background, I nearly had a brown trouser moment. Suitable advice was given, about the need to reform trains, move certain designated units from this or that siding to the maintenance shed (and visa versa) every night, let alone Fleet Control having to reform units/trains (on depot) in relation to mileage based issues.
Bottom line at somewhere like Wimbledon, the depot will need (in addition to simple overnight stabling for trains in their ready to move make up each morning), will need something like 10-15% of the overall siding space left vacant each night to allow for operational flexibility.