The dwelling together with any garage, garden and outbuildings, normally occupied by the claimant as his home including any premises not so occupied which it is impracticable or unreasonable to sell separately, in particular, in Scotland, any croft land on which the dwelling is situated; but, notwithstanding regulation 25 (calculation of income and capital of members of claimant's family and of a polygamous marriage), only one dwelling shall be disregarded under this paragraph.