Well, I just attempted to register with the DDS card. At the outset, they say they will need your service number, in order to confirm you are eligible. Having provided this, they come up with another requirement; provide your service ID card or go to an MoD web site to pay for your service records, in order to confirm you are eligible. And I thought I had done the confirming bit with the service number. I shall give it some thought before proceeding any further.