Curly

Hello all, We have had a fire risk assessment completed by a new company, who are gladly more stricter than past companies. My question is, that our main buildings were built in 1958. Some of the pick up points were concerning risks which are due to the building being built before such regs, whilst we complete as many pick points as we can. Some like the pvc windows and panels for example were fitted before such rules came into place. And the due to the cost of replacing these which would be enormous. So how do we stand in such matters, what reply do I give, If the cost is simply not practicable due to the age of the premises?