Paul - The Kirkhams are available theough Gerry Hawkridge of Hawk Cars, incidently the Hawk 289's are well worth a look at, Two of my friends drive Hawk 289's, one with a Weber equiped 289 Ford and the other a 4.0 Litre Rover.
The Crendon 427 is a car worth looking at, it is at the top end of the British market, is well capable of taking a big block, has an authentic looking round tube chassis and is generally a quality kit.
Andy