A wonderful model, well-photographed and the figures are very good. As for the original concept...well, in retrospect it seems complete madness, but I suppose at the time anything that would break a trenches and barbed wire deadlock was worth considering.
With regards the WW2 Panjandrum: There was a really superb BBC TV series called 'The Secret War' which was based on the book of the same title by Dr R V Jones, one of Churchill's 'boffins' and which was screened in Britain in the late 1970s. It featured, amongst many. many other fascinating things (including the invention of radar, the battle that the RAF had with the Luftwaffe in technological terms, the submarine war, development of ASDIC etc), some footage of the Panjandrum being tested on a beach 'somewhere in England'......and an unpredictable and dangerous beast it was too.
If anyone is interested there is some footage of it at:
https://www.youtube.com/watch?v=ZGn38C-ibjc It is a brief clip about 15.50 minutes into the programme, which also goes on to show prototype flail tanks etc.
Lucky it was not used in earnest on D-Day!!