Peter T Davies
Tresham Games have recently superceded this kit with a new offering: Development Kit 'D1'. D1 combines K1 and K6, together with some new tiles (there are 36 tiles in all), including Russet/Brown upgrades for the bottlenecks at Crewe, Swindon and Wolverton. I've just received my copy from Leisure Games.
That's a bit frustrating when they just delivered kit K1 to me today