Steve / Jim, I've just checked the lens, the blades are not moving at all when i change the apeture. I'll have to try and either find a manual for the lens to disassemble and clean myself or a workshop that can do it for me.
Cheers for the advice.
Rgds,
Dave
P.S. Jim, I do have some developing kit for my Minolta but am very much a beginner only having developed 2 films. I think this year I will have to put some time aside and learn what I am supposed to do properly instead of winging it.