Help with false ceiling/ lights and plastering etc.

You have to buy heat protected spot lights to not cause any problems

You need to remove the polystyrene as it’s a fire hazard , then you can drop the ceiling and put the cladding over or what you require . Hope this helps

its hard to identify what this product is likely to be without further investigation, a possibility is some form of foam underlay commonly used beneath laminate or engineered flooring. if you you do not wish to remove this then there are several ways protect against any issues of fire. 1 is to overboard the ceiling with a layer of 9mm plasterboard to provide separation between the existing ceiling and new ceiling installation. A point worth noting here is to be careful about the amount of additional loading you are applying to the existing ceiling joists, they will not have been specified to support sub ceilings and additional weight, so consider making your sub frame independent from the existing ceiling. the second solution would be to use LED fire rated downlights classed as insulation coverable which are double insulated with integrated drivers such as the Collingwood H2 LiteT 4.4W Fire Rated LED Downlight IP65 they are good safe units and offer little in the way of fire hazards. Tom Dorset Building Solutions Ltd

Strip the T&G out and investigate propally. you are creating a false ceiling anyway.No extra cost, just a bit more time but the peace of mind will be worth it.