Jon, the website is concise and straight to the point. Not overloaded with heavy background colours (that's colors to you of course
) or dancing logos which I personally find very offputting. As they say in a certain TV advert over here, "it does what it says on the tin", and that's basically all you need. It's certainly the sort of thing I'll be producing, although I'll probably make mine a bit larger (maybe five pages), but without the overkill that many sites seem to go for.
The true test of course is whether it works. Do you ask new clients where they found you, and if so, how much of it is due to the website?
Just out of interest, if the site is producing results for you, what would you want to get out of hiring a professional developer? I ask this, because I have a couple of friends who are site developers, but I wouldn't let them loose on my site. They are brilliant at what they do, and they have to demonstrate it by virtually making the pages dance off the screen. Far too flashy for me, and I'm scared to ask them to tone it down as I know they'd take offence.