Looking for some advice as to what brand of underfloor heating to go for. The only one that i can see is warmup which topps tiles stocks. Are there any other decent brands to look for.

Also is it worth installing the insulation boards for this type of heating. It will be put down on a conservatory floor that is going to be screeded.

i have received info from the following by post - floor warming company, devi heat, nu-heat. seen these and others at various construction trade shows but i only have experience with the floor warming co. happy with the product and the cost (plus i have one mat more than i needed as the tiler was an idiot and thought he'd save me some money by not using it. duh! keep meaning to sell it on ebay but haven't got round to it yet).
my floor is t&g chipboard on 2x2 battens over a concrete floor. floor void is filled with crown wool (and a timber floor will heat more quickly than a screeded floor, although i expect it would also lose heat more quickly than a screeded floor - not sure though). 18mm ply over the chipboard, mats set in latex levelling screed and then tiled over.

i would always use underlay unless you are struggling for height.

i used 3mm although vysal (a good brand by the way) wanted 6mm. if you are on screed underlay is a must or you will double your electricity costs.

cheers.