IMHO you should stop messing with the site.
If the site has radical changes as has happened recently - new front page and totally different forum layout - people will get pissed off.
Putting 'scotland' in the name excludes anyone not in Scotland so - with hindsight - not the best idea.
If you go to
http://www.aberdeenbikers.co.uk you'll find that the layout has been the same for a very long time. Nothing has changed. But it's still a very popular sight.
Having 'Aberdeen' in the name perhaps excludes others but motorcycle owners are generally more enthusiastic than car owners. One of the benefits is that the local theme encourages more people to join.
IMHO if you want the site to be a success change the name to something 'all inclusive' and stick to one design.
14 forums also seems a tad over-the-top for a site with less than 150 registered members.
Perhaps 4 would do... 'General Chat' 'Your Cars' 'Events' and 'For Sale/Wanted'.