As a bit of clarification (aka 2 bits). Caterham has sued just abut all accurate replica makers. Too bad Ford did not take such care of the Cobra. The only case they lost was against Birkin. As I read the case, there are some interesting points. The original contract from Lotus to Caterham was for continuing Seven production (the Series 4), and for supplying parts for all previous models (S1,2,3). At the official introduction of the Birkin, the entire Lotus Formula One team and Chapman family were in attendance. The Birkins were sold in S.A. through authorized Lotus dealers. Of course, the case was before a South African court, which may explain the absence of Birkin in G.B.
Not to PO my Cat brethren, but I find the Birkin to be an excellent Seven.