I spent another 8 hours at the city centre peregrine site today...it seems my misspent youth has followed me into old age! I can confirm that the juveniles seen by me today have red Darvic rings numbered B1, B2 and B4. I think B4 is the female. She certainly looks big. The quest remaining is to spot B3 hoping he is alive and kicking. The adult male is hopefully teaching it a few tricks over the wider territory.
I managed some of my best peregrine shots today even though it chucked it down and my lens kept steaming up. Having to put up with the odd drunk and a few hoodies I understand why the pro photographers keep away.