Cheaper than both of those is www.supanames.co.uk - £18 a year 35 meg space full CGI PHP unlimited transfer free domain (UK domains or £7.50 for .net .com etc) icdsoft prices are in $$ not what...
Not sure finding cheap good quality UK domain companies is hard. I hate to say it but it would be cheaper to get a hosting package with domain included. Or you could try a .tk although I personally...