Recently Nominet, the Registry for:
.co.uk
.org.uk
.me.uk
.ltd.uk
.plc.uk
.net.uk
updated their registration systems to allow dotUK domains to be registered for between 1 and 10 years.
The 1 year price has been "loaded" by Nominet ~50% to encourage people to continue to register in 2 year increments.
When a domain is registered for multiple years, the administative cost, card-fees, processing requirements etc are shared across multiple years.
With a 1 year registration (where the "workload" is the same as for a 2 year or even a 10 year domain name registration) but the period is shorter, this makes 1 year .uk domains just as expensive as 2 year registrations.
Because of this, Astutium Ltd through our registration site at www.astutium.com have decided not to offer 1 year .uk domains, but to reduce the price of 2-10 year registrations - making our 2 year price less than our competitors 1 year price !
We have also removed the restriction of only being able to renew domains in the last 180 days of their period - you can now renew them at any time (upto a maximum of 10 years remaining on the registration)