Thanks for the info Paul.
From what I've gathered so far on a web page it seems that those registered from March 23, 2006 went into the higher bracket.
Pedantic I know but I intend to keep the car for many years ... 10 years [for example] means that at the £555 rate and plus the inevitable increases, that'll be £6k plus going to the rob dog tax man as opposed to, say £4k.
We all have principles of one form or another !
Like many of the taxes, 'road tax' has long since been 're-directed' or at least certainly not been spent on the roads around me !!!!