.... if a picture is worth a thousand.
That's not a D15, for a start.
Easy enough though. D60S short wheelbase T110L code tipper ( none of that fancy 'dump' stuff here )
Same cab, same 236 cu in engine as a D15 though it should have a T110-xxxxx code on the cylinder block rather than the T222-xxxxx that would be on a D15.
Chassis rails deeper and thicker, suspension and so on suitably heavier, PTO drive to hydraulics. I'd be surprised if that wasn't all original, only easy item to swap would be the engine. 1941-45 only, military only - note the tow hooks and interchangeable British-pattern wheels. That chassis number will be in the range on the T110L series military manuals and parts lists. I will have it listed somewhere but I'm in Aberdeen and my paperwork is in Falkirk. Feel free to ask again if you meet official resistance, as it were.
There were civilian code T110 trucks, but they were left hand drive only and I've only ever seen one outside the US.