Sounds as though you and Colin are going to get on great, why not sub the work to Colin, if he's agreeable, and go along as an associate. You could make a percentage and learn as you go and the experience you'll gain is worth a fortune. Exchange cards and promote each others business, we really should be doing more of this given there is a large window cleaning section and carpet cleaning section ready made on clean it up. It would not suit everyone but some would benefit.
Simon