Look on your doorstep, village halls, green groups, transition towns, - in fact why don't you pay a few quid to hire a hall for an afternoon and invite everyone in to see what you've got, obviously either in an area where you've done a couple of installs or in an area with loads of potentially great d/C ratings. Do it through the parish council on the back of your concern about rising fuel bills for their householders. Local agricultural/home shows - I've only ever paid more than ÂŁ100 and it nearly killed me, it was ÂŁ125 lol. Best one was ÂŁ30 for 70k of business at a show 10 miles away from us.
Shows are hard work but almost always work for us, we just didn't have time to do many last year because we were too busy. Aaahh remember those days .......