The NAF ruling you refer to relates to UDRP a policy established in 1999 for global domain names (com net org etc)
Nominet chose to ignore the wording of UDRP and instead decided to write their own policy in 2001 called DRS .
UDRP requires that the domain name to have been registered in bad faith AND used in bad faith.
Nominet DRS requires that the domain name to have been registered in bad faith OR used in bad faith.
This is a fundamental difference which allows decisions to take away co.uk domain names registered a long time ago, in some cases even before the complainant existed or registered a trademark or simply established "rights" (with DRS the complainant doesnt even have to have a registered trademark).