We had an instructor called Denise who helped me with my stage 2! Could it be you?
Yes Judy was Graham's other half who sometimes gave I lessons I used to ride her horse called Chablis.
I remember the pub rides well and the hacks over to Derby day at Epsom and yes the weekly shop at Waitrose...
I too have just found out Clock Tower has been converted into houses/flats :(
I used to work there in the mid 80's when Graham Rouse was there :) Lots of happy memories, Nimbus was a favourite as was Rosie and Thor (livery). Would love to hear from people who were there around 1984 - 87 ish :-) Nx