do you have an examples jon?
I bought an old canon a1 recently, and I was disappointed with the results too - I posted some on a thread here to get some feedback to try and see if the problem was me, the film, the camera, the developing (asda), the scanning etc.
In my case, as I had been using it on 'auto' (wasn't brave enough to go whole hog yet), the over exposed shots were due to the scenes being very sunny and the light meter (as its older) perhaps not dealing with it that well. when I go away next week, im going to use the exsposure lock to try and combat this. I think the scanning asda does (even though it says hi res), is pretty shoddy. its clear they don't have time (for the price it is, I wouldn't expect) to pay much attention to anything. some of the lighter frames havnt scanned properly as the scanner has skipped across frames etc. As its only £1 to get the CD, when I get my photos from Iceland developed, I will get them put on CD just to see what I've managed to get (not all that confident), and then I have borrowed my friends neg scanner (as long as I can get it to work, the other one I borrowed from him just wouldn't play ball with my machine) and re scan any that I think are worthy of more attention. I found some shots needed some tweaks of levels in photoshop. I think I was expecting too much, in combination with the other stuff mentioned.
if you can post up some examples, maybe some people can help - as the feedback I got helped me a lot