Thanks all.
Just in from a 25mile ride after I lowered the saddle more than I normally would. No small of back pain when I got in though I do have a bit of upper back pain but I have that on a long walk as well so can't blame the bike. I think that seems to be a general activity thing. Sometimes think it is much easier to be a bone idle git. LOL. During the ride I got out of the saddle a lot and spent more time spinning in smaller gears so something is working which is a relief. I'm definately thinking of either Yoga or Pilates as my gym runs free classes. Unsure which is the best though. On the core strength, I always include a good set of squats at the gym in an attempt to keep core strength up as well as a decent bench press etc workout.
Bigjim I am recovering from a prolapsed disc so can sympathise with the back pain.
My work runs Pilates once a week at lunchtimes and I can highly recommend. I have also tried yoga in the past which was excellent as well.
Pilates will target your core far more effectively than bench presses and Squats. It will also build in stretching exercises which if you are anything like me do not feature high on the agenda but are actually worth their weight in gold.
Pilates is a very good workout and if you are having lower back problems ask to be shown the mermaid stretch which sounds very gentle and sedate but ask your hip flexors that questions afterwards!