Little Blue asked me about this on another thread, so started a new one for anyone who also may be wondering the same thing!!
I have now two separate holdings as such with the new land. Wanting to move the goats, I enquired about an additional CPH number, and was told by Animal Health that so long as my other holding is 5 miles or closer, then I can just use my current number. As I have said, we can actually see the fields from our current holding, and as the crow flies - as in over the fields, its probably 3 miles.
We drove from one place to the other, going in two different ways, as obviously road distance will be more. One was dead on 5 miles, and the other 4.9 miles. Therefore, I meet the criteria for using just one number. As to being in two different counties, yes, technically I would have a different area health, but assume as my main holding is in Derbyshire, that will do. This must happen a lot here, as we border, Lancs, Cheshire, Derbyshire, S Yorks, and Staffs, so livestock owners must regularly take livestock from farm to farm etc and maybe go through two counties and back in just a few minutes!!!