If you've explained the details to your insurance company fully, then they should be using their legal team to go after the sub contractor's insurer anyway
This is what is happening.
The subcontractor is a huge company and will be insured. But the people on the ground are morons, so it's easier to let the insurers deal with it.
Had my misses car damaged by a contractor vehicle delivering to a site, on the other side of the road! Thankfully came out with a repair to the clear coat in under an hour.
Their site boss was very un interested .
This is what is happening.
The subcontractor is a huge company and will be insured. But the people on the ground are morons, so it's easier to let the insurers deal with it.