Possible Clues:

• Place to fill the tank
• Esso in Essex, e.g
• Fill up here, as puppy maybe lost wandering into allotment
• Garage patrons' toilet in need of facelift
• Garage to stop Reliant rattling...
• What driver stops at -- wants patron's toilet badly
• Filling up location?
• Fuel supplier of sort with potential to change
• Filling place for head removed from hospital, rotten, to be reformed
• At which to fill up