Although these suppliers don't match your search for Castles in Eton, they are within approximately 40 miles and could still be of interest.
Venues, Castles, Southampton, Hampshire
God’s House Tower (GHT) is a stunning multi-purpose venue at the south eastern entrance to Southampton’s historic and beautifully-preserved Old Town, located at Town Quay Road on the edge of the city centre. Set within the city’s medieval defensive walls, GHT offers a unique glimpse into Southampton’s past, and after an extensive and sensitive refurbishment is now thriving in its present day incarnation as a cutting-edge arts, heritage and events venue. (Castles in Eton)