Dear Barmaid,
I live on Watchbell Street , know the people who now live in Bellmount.and have seen an excellent photo showing the house as it then was, boys who belonged to Mr Pretty's school plus girls from another school across the road at No. 10. This was in a brief article by Frank Palmer: Watchbell Street in the mid 1870's (information much as on the Rye Museum Education page you saw) in Rye's Own, Issue 115 (eb '04) . I could send you the page by email if you'd like. Was your greatgrandfather Mr Pretty??
I'm afraid I don't know anything about 'the scandal' but a group of us are embarking on a Victorian Rye project and I shall investigate. The present occupants don't know anything about Mr Pretty but the man's grandfather may well have been the next occupant. Will let you know if anything relevant turns up. And if you manage to get more information, I'd be interested!