Originally Posted by
SKT-DK
Wow… Just wow.. Pretty appalling suggestion to throw at a customer

It's actually the best advice to offer, at least in part. Calling BA is the way you access ticketing staff. No-one at Gatwick is able to do that. It's usually possible to deal with things online, but for slightly more complex things, calling BA is absolutely the right thing to do.
Going to Heathrow won't help a lot usually, so that wasn't great advice.