Thank you for your help. I have been struggling to find the caliper without going to Lexus and taking out a mortgage!
I think I will try going the refurb road first. If that fails a replacement it will have to be.
Malc re the VSC issue. I never got to the bottom of it. It has behaved itself since my post way back and has not come on again! I suspect a loose connection to a sensor, although I am not sure nor why it now behaves. Of late the water temperature gauge sometimes drops to cold but always seems to sort itself out after a few miles. Again I suspect a loose connection. I will have a good look when doing the caliper.