I love the Liberator from Blakes 7, a fantastic design. There are three kits out there that have been available over time, 1st was the Comet Miniatures one,bottom picture, then the Titan Find, top picture, and third the Masterpiece models kit.
At the time, that was probably 2 years ago I wanted a kit of the ship. The Comet one was going for big bucks on Evilbay and is quite small. The Titan one is 14" excluding antenae with clear plastic engine halves to enable lighting and was $130 plus shipping, a bit too big for display perhaps, but when I saw the Masterpiece kit I decided to buy.
This kit is 12" long and cost $69.95 plus shipping.
It is the only one possibly still available to buy now.