I've been playing autoharp for nearly 20 years and I still don't understand why the standard autoharp setup emphasizes the key of F when so few other instruments play in F very often. Perhaps it's because F is a good, middle of the road singing key and suits a lot of people's voices. With a tempered scale (which we all use, pretty much), it shouldn't be "lighter" or "darker" than other keys, just lower them some and higher than others.
Of course, you could probably talk to Mark (who I know makes lovely instruments) about restringing it and cutting you some chord bars in A, D, G or C - more common keys for jamming. It shouldn't be too hard to make the conversion.
By the way - Sinsull, your problem may be due to the frame pulling apart below the chord bars (or elsewhere, I suppose). I had a similar problem after a hotel porter dropped my Keith Young chromatic - evidently from a pretty significant height. It was annoying to repair mainly because it involved restringing the instrument, but that's a good thing to do from time to time anyway. Other than that it took Keith very little time to make it as good as new.