Remember the Crusader with the 5.5 inch ?
I got that out.. then decided to trash that idea. A few minutes contemplation then decided to go more '46 weapons.
Back story synopsis.
With the surprise Soviet attack on Western Europe in July 1945 there was an acute need for more anti Tank weapons. Of course the 17 pounder was one of the best in the inventory so an expedient SP mount was developed using obsolete Crusader Chassis. Taking the que from the Soviet and German Tank Killers like the Su-85 and Jagdpanther a box like superstructure was quickly developed to mount the 17 Pounder. These severely taxed the chassis and most of the Crusaders speed and agility was compromised, but still the Arbelest as it came to be called was a terrific stop gap until more Centurions and Comets came on line.
The gun is "on loan" from an Academy Achilles. I know this has been done before but it just had to happen.
It was either this or an early British Anti Tank Guided Weapon carrier, perhaps using the R-7 Missiles, but decided to go the more practical Stop gap measure of the SP 17 Pounder.