Glad to learn that you are getting somewhere with this.
Loss adjusters are merely companies that settle insurance claims in the most efficient way (spending the least amount of money that will satisfy the minimum requirement).
If the original developer cannot be coerced into correcting the fault or has gone out of business, the loss adjuster is working on behalf of Zurich who, as the insurer, now have the job of fixing the problem.
Sounds like you have won and it is just a matter of (a short) time.