Aidan Lister's dashboard

I can't register my phone - I've tried a dozen times over the last three weeks. I get this completely useless message, "There was an error validating 0794 xxx 4273. Please try again in a few minutes.". It's a UK number, so I'm using +44 as the prefix. If I change a single digit, then it appears to work as normal. I'm sure the number is correct.