You could have parked in Springkerse retail park area in Stirling. Can think of several places, next time just ask .Stirling would be good. We spent an unhappy 2 hours in the gathering gloaming trying to find somewhere close by, and went through some pretty places - Dunblane, Bridge of Allan etc - nowhere to park up, no laybys, no car parks, no suitable side streets. Ended up paying £10.50 to park at the first services on the A9M.
Now, that's a real bugbear for me. Most motorway services let motorhomes buy parking for the night, and that's useful to know if you're in a pinch like we were, but precious few have designated motorhome or caravan parking, and no thought has been given to motorhomer or tugger needs. None of the staff on the site knew where we were and were not allowed to park; the lorry park was full anyway (and most of them had their refrigeration units running - deafening) so we ended up in the car park shared between Burger King and Travelodge, with people getting in and out of their cars and going for food or the loo or moving their suitcases in and out of the hotel all night, many of them being very loud about it. Both car and lorry parking was on a really bad camber. A very poor night's kip was had by all, and we wouldn't go on another service station unless we were utterly desperate.
At £10.50 I guess it's cheap for a night with access to a loo and food, but for £10.50 you want someone to have put a little thought into what a motorhomer will need. If enough of them did sort their act out, there's no reason they shouldn't operate as a network of Aires of a kind and bring in extra revenue for the site owner.