wilderness - 6:12 pm on Oct 2, 2011 (gmt 0)
is that users are going to be UK only - but I might want to allow US,CA,IE,AU,NZ usage too (mainly so webmasters/press can try it and write about it).
I used something similar for more than ten years, based upon IP.
The most effective method is to "deny all", then "allow the UK ranges".
For the other country ranges, I would suggest monitoring your "raw logs" (after a while the 403's will jump out at you), and then making very small Class D exceptions for those that your desire access "on the fly".
To allow the entire US and CAN IP's is far too extensive a task.
The Oceanic (AU and NZ) are easy enough to separate from the other APNIC IP's.
I've no experience focused upon Ireland's IP's, at least as an individual group, and thus I'm not aware of how extensive that category is.