I'm the maintenance guy for a client who owns a 1930's ex toffee factory which is up for redevelopment into housing. In the empty office building and ex social building there are cast iron rads that they are heating to stop freezing. I've advised them to drain them but they tell me that the developers might want to re use them and if drained they will need recommissioning. I want to know if this is true as they are paying £800 a month heating bill at the moment until the weather warms up. Outline planning permission has been put forward but no actual sale yet.