You need to complain to the FSA as the broker that sold the policy to your mother did not'Treat Customers Fairly' The FSA are hot on the trail of brokers who chase commission payments for policy's that are not complying with the FSA outcomes.
Its up to the broker to do a financial and proper fact find and present it to the company for processing. The company in question will get back to the broker and then the fun will start. You are right it is not up to the company to check what