I was in for a surprise when I checked my emails this afternoon; I had a reply from Sir Neville Bowman-Shaw (SamUK Lift Trucks Ltd) identifying the larger forklift as a Boss D42; capacity of 4200 (kg I assume) @ 1200mm load centre with perhaps a 4.0m duplex mast. Engine is likely to be a Leyland 680 diesel and a British Twin Disc transmission.

There was a G series of this forklift, with a 4m width designed to handle containers 20-40ft in length with the lift height to stack up to 4 containers on top of one another.

Thank you for all the help on this, I believe I have only one Boss brochure kicking around somewhere and its certainly not for a machine of this size!

Best regards