[Tagging] Clarify tag access doc

[Philip Barnes]

On Tue, 2012-09-11 at 21:03 +0100, Rob Nickerson wrote:
> 
> Although I don't know the history of the access tag, I would expect
> that "designated" and "permissive" might have something to do with
> Public Rights of Way in the UK:
I think they refer to England and Wales. Scotland has different access
laws, and I suspect N Ireland is different again.

Phil