Yes, I plugged that into maps.google.co.uk before I posted. (Did you try that?)
Am I to understand that the visitor centre is really on Gordon Rd.?
If so, why not publish that? Is it a secret? Otherwise I'd expect to have to go to Westwood, then wander around and ask people on the street where to find Hornbys. Or maybe Hornbys is so big that I'll just get sucked into it's accretion disc and I shouldn't worry about whether I'll be able to find it, because it'll find me once I'm in the vicinity.
To me, Hornby's address would be like me listing my address as California, 93065-2159, instead of 1706 Cochran St, Simi Valley, CA, 93065. While California, 93065-2159 might theoretically be enough for the USPS to deliver mail, it's not particularly useful for normal people.
N.B. That's not my address, or even the address of anyone I know.