akgray,
How old is this cistern and where are pipes/cistern located with regards to roof and eaves, have you got any photos of tank/cistern and pipe work within the loft?
If the cistern and pipe work is insulated well within the loft space, with a ventilation gap beneath the cistern/tank, then this should prevent both pipe freezing and undue warming. Providing enough area/space has been left between roof and this set up, would be looking at at least 300mm between cistern lid and nearest part of roof.
How old is this cistern and where are pipes/cistern located with regards to roof and eaves, have you got any photos of tank/cistern and pipe work within the loft?
If the cistern and pipe work is insulated well within the loft space, with a ventilation gap beneath the cistern/tank, then this should prevent both pipe freezing and undue warming. Providing enough area/space has been left between roof and this set up, would be looking at at least 300mm between cistern lid and nearest part of roof.