For comparison, we pay £6.99 for an annual co.uk domain renewal with Fasthosts.
However, for a .com, a single year's renewal is £11.99.
Yeah, yeah, I know, Fasthosts isn't much better than 123-Reg, but we only use them for domain registration, and to initially sort out glue-records to our own DNS servers, so our exposure is low...
At the end of the day, most domain registrars are a similar level of dross.