UK2 have always been the worst in the business when it comes to add on charges. I transfered all my domains away from them back in 2000 when they tried to charge me £20+ just to change nameservers on one domain.
My advice to everyone is transfer your .uk domains to another registrar such as Heart Internet, for all your other domains you can administer them for free at joker.com if it says that your registrar is joker.com in the whois. Full instructions to transfer a .com away are
here.