Is my supply address differing to my billing address affecting my upgrade to the DCC?

I’m wondering about the significance of the ‘supply address’ as opposed to the ‘billing address’ on my account.

This is in part prompted by my smart meter’s stubborn refusal to be adopted by DCC. When I visit https://smartmetercheck.citizensadvice.org.uk, I’m consistently told that ‘we can’t find your meter.’ One possible explanation for this is that the ‘supply address’ is in a different postcode from the meter itself*, and postcodes seem to have some vital role to play in any aspect of energy supply. Is this a possibility?

Another reason for my concern is that if I visit https://switch.ovoenergy.com in order to find out how much I’ll be paying once my fixed-price contract runs out, I see a message reading “Good news! We already supply your home, so we can give you a more accurate quote  ...” But when I examine the Tariff Information Label, I see that this ‘more accurate quote’ is for single-rate electricity, when my meter is set up for E7. In order to see the equivalent two-rate tariff, I have to enter the address of a house half a mile away in the next postcode, which it shares with my ‘supply address’. So how come this function can’t see that I have an E7 account? 

Incidentally, it did cross my mind that it was the distance from the nearest communication masts that was making it difficult to get the meter adopted by DCC. However, all my postcode investigations having led me to intimate details of my neighbours’ meters, I plugged in the MPAN for the house next door to the CAB tool and was peeved to see that their meter had been migrated last year: 
  

Your electricity meter's working in smart mode

Supplier: E.ON Next Energy Limited

This means your meter should automatically send readings to your supplier, so you don't need to send them yourself.

It's working in smart mode because you have a first generation (SMETS1) meter that’s on the smart meter data network. The network connects your smart meter to energy suppliers ...

So poor communication was not likely to be the reason.   

*  I guess that this is because this rented cottage was earlier occupied by the estate’s gamekeeper, with his bills paid by the estate. The manor house is in the next postcode, so someone made that the ‘supply address.’ I did have to change the address for correspondence after I moved in several years ago, since my bills were being delivered to the manor house. This hasn’t hitherto caused problems, until perhaps now.