This section applies where—
a secure tenant has claimed to exercise the right to buy,
before the landlord has made to the tenant such a grant as is required by section 138(1) in respect of the claim, either an initial demolition notice is served on the tenant under Schedule 5A or a final demolition notice is served on him under paragraph 13 of Schedule 5, and
the tenant's claim is established before that notice comes into force under Schedule 5A or paragraph 13 of Schedule 5 (as the case may be).
If, within the period of three months beginning with the date when the notice comes into force (" the operative date "), the tenant serves on the landlord a written notice claiming an amount of compensation under subsection (3), the landlord shall pay that amount to the tenant.
Compensation under this subsection is compensation in respect of expenditure reasonably incurred by the tenant before the operative date in respect of legal and other fees, and other professional costs and expenses, payable in connection with the exercise by him of the right to buy.
A notice under subsection (2) must be accompanied by receipts or other documents showing that the tenant incurred the expenditure in question.