Series 2A Fire engine with rear coils and leafs

Hi I just bought a 2A and it has rear coils (with shocks inside them) as well as the standard 109 leaf springs, so thats three shocks per side. It was built this way because it has three rear water tanks totalling around 800ltrs (800kg) of water as well as the fire pump and equipment. I have taken the coils off because the shocks inside them are rusted through, I could leave them off and just use the leaf springs but not if I want to fill the water tanks. Has anyone seen this arrangement before or know where I can find new ones from? Under the Red paint it is green so supplied to the military I guess?

The only fire appliance seen fitted with supplementary coils was in OZ on a bushfire landcrsr , which was a farmers bodge . In UK series were usually fitted with HD springs and Aeon rubber spring assisters in fire engine
application . Even the tacr1 was not fitted as you describe and was based on a series 1 ton . The tacr2 was based on the rangerover with a whole extra tag axle to get its MAM up .
The extra coils I suggest would take it above its legal MAM for use on the road , and most likely are a non rover add on

Thanks for your reply........ they were certainly well fitted not bodged but I took them off leaving the attachment brackets that have been added to the chassis. I looked on Ebay and think I have found an identical set of four from a Jaguar XJ8, I won the bid at £20 so its worth the chance. Top picture shows the truck in service at Perranporth RAFairfield where it was in use until 2015