This section applies to the assessment of compensation in respect of the compulsory acquisition of an interest in a dwelling which—
has been constructed or substantially modified to meet the special needs of a disabled person; and
is occupied by such a person as his residence immediately before the date when the acquiring authority take possession of the dwelling or was last so occupied before that date.
The compensation shall, if the person whose interest is acquired so elects, be assessed as if the dwelling were land which is devoted to a purpose of such a nature that there is no general demand or market for land for that purpose.