@matigo I don't think these people understand the difference between front-ends, back-ends, and elbows.
The 7 digits at the front are an industry standard, but there's also another format (in the same standard) that's 18 digits and expresses the DDDD (D*DDxx) portion, as well as a bunch of other stuff; absolutely no idea why they had to start from scratch.
Makes no difference to me: we (head of IT and I) just generate that number by concatenating a bunch of existing fields. I'll just wait for Bobby Tables to show up.