Do gas safety regulations allow its use?

It is safe to use this boiler cover so long as you follow the minimum safe install distance as required by UK Gas Safety Regulations. This can vary due to your boiler but for most purposes 75mm above the boiler flue.

Just be sure to install this cover within regulation distance above the flue to ensure that steam and unspent gas from your boiler safely escapes and does not re-enter the flue and into your boiler or property and you're good to go.