The 60 reviews here on Trustpilot deal largely with the customer service of the company supplying the product but, if you read through them carefully, you'll find several direct references to the product. e.g. "The Nitro flametect I am using on Polyester felt seems to do the trick (held a lighter under it and no flames), but it does make the felt feel 'clammy'- sticky is far to strong a word, but it certainly changes the feel of the fabric. Looks fine though"
https://uk.trustpilot.com/review/fireproofspray.co.uk