I can't speak for the FWB Sport, but a Mercury S in 177 was the first rifle I bought with my own money (£65 from a company called "The Mart" by mail order) and it was a fabulous rifle that served me well for about 21 years until I bought a house and had to turn the majority of my air rifle collection in to furniture to sit on and eat off.
If any one on the forum has BSA Mercury S serial number WH 01266, I'd dearly love to buy it back.
The South of England has 2 good things, the M1 and the A1. Both will take you to Yorkshire.