Yes, such a document does exist and has been published by the Department of Health, according to the MailonLine.
"Health chiefs advised yesterday that homes should be painted white to reflect the heat. The Department of Health's Heatwave Plan for England, which is designed to counter the effects of climate change, reports that painting brickwork white will cost a homeowner around £3,750. Carpets should also be replaced with tiles or wood, and metal blinds swapped for curtains with light linings, to keep rooms cool as temperatures rise. Changing flooring comes in at a touch over "2,000, whilst installing ceiling fans can cost £545."
Oh dear, does that mean our MPs have now got to pay for all this themselves? Until they find a way that it may comply with the test of 'reasonableness'!
H/T: Old Holborn