it would still not help at around 3 mile range as the poster is the situation is exactly as the installed cabinet out side the exchange
Now it is not all doom and gloom as some exchanges can have the FTTC DSLAM installed inside the exchanges.
Not sure why that would help as the distance to the cab/exchange will be the same and far to far for fibre
Have you tried using the Better Broadband for Norfolk when and where checker? http://www.betterbroadbandnorfolk.co.uk/default.aspx
There is a postcode checker on the right hand side.
You may also want to keep in contact with the Better Broadband for Norfolk BDUK/SEP team via BetterBroadbandforNorfolkProject@norfolk.gov.uk giving them your landline number and full address to see if you are within scope of the programmes.