randomly hit the keyboard and produced:
From part L :
2.10 The need to conserve the special characteristics of such historic buildings needs to be recognised. In such work, the aim should be to improve energy efficiency where and to the extent that it is practically possible, always provided that the work does not prejudice the character of the historic building, or increase the risk of long-term deterioration to the building fabric or fittings. In arriving at an appropriate balance between historic building conservation and energy conservation, it would be appropriate to take into account the advice of the local planning authority' s conservation officer.
The 'advice' of the conservation officer is in fact legally binding on a listed building so this is in effect an exemption, though I agree not phrased as such. And many COs are not allowing extra (or even any) loft insulation as you propose because of worries concerning build up of vapour in ancient roof structures.
And I agree this is silly !