I would agree, the brickwork on your house is pretty bad.
No doubt the NHBC will side with Countryside and say it is "within tolerance" in any event I doubt it wont be knocked down and re built.
The best you can hope for is a payment (compensation) to accept the poor workmanship as full and final settlement of the matter. It is known as the Ruxley Rule.
In cases where rectification would be disproportionate, the Ruxley ruling allows a small cash sum to be paid instead. Misuse of that ruling strengthens the case for accepting poor workmanship tolerances in my opinion.
Previously I know of an RICS surveyor who assessed £425 instead of rectification for roof straps that were too short and £1,600 instead of rebuilding for a utility room that was half the contracted size. These probably were correct uses of 'Ruxley' but the sums don't seem anywhere near enough!
I would suggest you don't settle for less than £1,500.