Re:
Thank you for all advise, I took the blocks out and filed the blocks to achieve the required toe-in as described, Ia lso cleaned the rim with acetone. I also checked all the other issues mentioned above, but there was no issues threre. The brakes are now working perfectly well without any high pitch noise.
But its about time to think about replacing the blocks. What is the best blocks available nowadays for the Campagnolo Record brakes?