Thank you everybody for your helpful advice. This is my first time at a forum of this type and I am staggered at the knowledge out there and the willingness to share that. I have all these replies in just 10 hours.
I have had this car from new and it's completely original. So I am against exchange calipers. Conceptually I am much happier repairing the current units and in thenlight of all the comments, that is what I shall do.
Once again my grateful thanks.
