I built an extension around six years ago and had 100mm Jablite under the slab as insulation. This was passed by Building Regs (full plans) but when the inspector came to check before the pour he said we don't use Jablite anymore! Luckily when I pointed out that this had been signed off he let it go. So, I am now building a new extension and would like some advice on what type of insulation people would recommend these days under a new concrete kitchen floor - Celotex XR/GA4000 perhaps?