Bubonic Plague was around in the 17th century, Union Street was levelled in the 19th centrury as far as I know. I'm not sure the non-modern history of the Belmont Street buildings other than No 17. Back in the days of steam radio, the station 2BD was at 17 Belmont Street, where One Up and the ethnic cafe are now. There's an article on the Leopard magazine website about the BBC history. There are several articles and advertisement in old Leopard magazines about the BBC's landlord but you'd need to search the microfiche records, though the records may be computerised now.