All, please see the following response from the council:
"Hi Mr Shelton
The Roads Officer did carry out some investigative work at the location and determined that the car-wash did not have drainage facilities on-site and were therefore relying solely on the road's surface water drainage for the dispersal of the water. This was established to be overloading the gullies and the detergent-laden water was spilling onto both footway and carriageway and causing the damage you have noted. A number of interim repairs have been carried out between last summer and now.
This department is currently in the process of following statutory procedures to enforce remedial action by the owners of the car wash which may, as there is little evidence of the required work, result in the issuing of
a statutory notice, insisting remedial work be carried out, under the terms of the Roads (Scotland) Act 1984. Failure to comply with this can result in legal action.
Please accept my apologies for the length of time that this issue has been inconvenient to you, but please be assured that this department is strongly pursuing the matter."