Hi

can someone advise, regards fire door seals, some have a nylon brush type on both sides and along the top but others have rubber blade type, which ne is correct and is there a preference ? Thanks :) 

You seem to be describing combined intumescent fire and smoke seals, both are suitable. When fitted the brush or blade should lightly contact the surface of the door edge or door frame to provide an effective seal to restrict the spread of cold smoke.

The brush type tends to be more durable but the blade type are more forgiving in terms of the door self-closing and overcoming the resistance fro the seal.