VOSA test = VIC.
this is NOT required for Cat D.
cat C i understand it is required.
there is no requirement for an MOT for cat D, the current expiry date applies.
so you can buy it as a Cat D (which i would think this is at worst) and drive it away no
problem.
one thing to note:
keep checking to see if the road tax is valid. depending how the insurance company work it they may technically take ownership before they sell back to you. then the road tax may have been cancelled.
They may well ask for the documents, V5 etc then send these back to you if you decide to buy. this probably depends on the insurance company itself.
It can get messy if the insurance company do take the V5 and are slow giving it back so note down or copy it so you can apply for road tax etc if required.