Debatable if in fact uses butted / double tubing but here's a few specs on this one plus weight.

Frame:
Made in England by Phoenix 4130 cold drawn seamless alloy steel tubing (Lambert called it 1027)
lugless, low temp hand brazed
Viscount dropouts, 126mm axle width

seat tube angle 73 degree
head tube angle 72 degree
head tube length 15.5cm end to end
top tube 57cm ctr-ctr
seat tube 58cm ctr-ctr
down tube 63cm ctr-ctr
chainstay 42.5cm
seat stay 53.5 ctr-ctr
wheelbase --
weight 1989gm

[IMG]DSC_1096 by carrera247, on Flickr[/IMG]

[IMG]DSC_1093 by carrera247, on Flickr[/IMG]

[IMG]DSC_1091 by carrera247, on Flickr[/IMG]

[IMG]DSC_1090 by carrera247, on Flickr[/IMG]