Hello Topper welcome,
Bit of advise for you as you are aware that window cleaners in Scotland must be licensed by law.
If you buy a window cleaning round off an unlicensed window cleaner then you have no legal status if it goes wrong. Only licensed window cleaners can sell rounds and canvass doors, if not licensed then it is illegal. So make sure if you buy anything it is from a licensed window cleaner to cover yourself.