My consultant called into my GP's and saw the practice nurse the one day that we were out doing a leaflet drop. She was given all the information about it etc and I know of several people, myself included that have since been and got the countdown vouchers from her.
It is not only in your interest to get the vouchers but also the GP's and the HA because in the long run it will save the HA money if people are able to get the vouchers and lose weight.
When I went to see our practice nurse, I took my SW red/green book so that she was able to see that I have been attending class. You need to have a bmi of 30 or more. I got weighed to just check my weight against my book and that was that.
Why not speak to your consultant and see if she can arrange to visit the GP or practice nurse to give them some more information etc. It worked for my consultant,myself and my friends so you never know it may work for yours and you.