Operations
Mobile or workshop fitting? Offer both, cleanly.
Mobile and workshop fitting are different products with different costs and constraints. The trick is to treat them that way.
Price them separately
A mobile fit carries travel and time a bay job does not. Give each its own price so neither subsidises the other by accident.
Schedule them differently
Workshop jobs fill bays; mobile jobs fill a van route. Routing mobile work by distance keeps the day efficient and the diary honest.
Let coverage decide
A mobile radius keeps van jobs reachable, while workshop customers simply see how far they are. The customer always sees the option that makes sense for them.