Can't answer that one. Did you ask them about it? I know that mapquest shows no locations found the address, but does show it for Maidstone, which is literally on the border of Windsor. The builing must be JUST outside the Windsor city limits. Can't explain the 2 numbers or different phone answering methods...
"Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason than that of blindfolded fear." - Thomas Jefferson