I believe the main difference between hot and cold hose is how much pressure they can take when hot. Some hoses blow up like a bloon. I doubt a hose would mealt. Heat retention doesn't seem to be a main factor in building hot hoses either, just the stability of the hose.
I've use brodex heavy duty for the past 6 months and it's been ok, not perfect though. I've heard that gardiners are bringing out some purpose built hot hose soon.
On a side point, if you are suffering a drop in pressure then it might be that your temperature is too high and creating back pressure in the boiler. Or see if you are getting kinks in the hose as it turns supple.
Simon.