2 step verification

i was signing in on my iMac and myiphone pops up with the 2 step verification password, however saying that my iMac is trying to sign in to Apple ID in a different part of the country!! ie live in London and it said logging in from Middlesbrough! I'm super worried as I recently sold my old iPad on eBay up north. Is this just a glitch??? I've changed my password now and even rang apple support and they said it's fine. Thoughts? Advise?

Thanks