In the case of a dwellinghouse built on or before the first day of September, nineteen hundred and forty-two (not being a dwellinghouse to which paragraph (c) of this subsection applies), any increase in the value of the dwellinghouse:

“Provided that no account shall be taken of so much of any such increase as brings the value to an amount that exceeds by more than fifteen per cent the capital value as at the first day of September, nineteen hundred and forty-two:

In the case of a dwellinghouse built after the first day of September, nineteen hundred and forty-two (not being a dwellinghouse to which paragraph (c) of this subsection applies), the capital cost of the dwellinghouse when built and the cost of any improvements made to the dwellinghouse after it was built:

In the case of a dwellinghouse purchased after the twenty-second day of February, nineteen hundred and fifty, and let to a new tenant on or after the tenth day of December, nineteen hundred and fifty-one, and after that purchase, the capital cost of the dwellinghouse to the landlord:

Any increase in rates or insurance premiums or other outgoings payable by the landlord in respect of the dwellinghouse:

Any increase in expenditure which relates to the tenancy and is met by the landlord for the benefit of the tenant.

Any increase in the value of the property:

“Provided that no account shall be taken of so much of any such increase as brings the value to an amount in excess of the capital value as defined in the Valuation of Land Act 1951:

Any increase in rates or insurance premiums or other outgoings payable by the landlord in respect of the property:

Any increase in expenditure which relates to the tenancy and is met by the landlord for the benefit of the tenant.”