Paragraph 5 (c) may be of relevance to you mayhem?
If you do go down this route, ensure you notify the landlord/housing association first. You could inform them that if the repair is not undertaken within the next 14 days you will have it repaired yourself and send the bill to them.
1. Disclosure of landlord's identity
(1) In a lease to which this section applies (as to which, see sections 13 and 14) there is implied a covenant by the lessor -
(a) to keep in repair the structure and exterior of the dwelling-house (including drains, gutters and external pipes),
(b) to keep in repair and proper working order the installations in the dwellinghouse for the supply of water, gas and electricity and for sanitation (including basins, sinks, baths and sanitary conveniences, but not other fixtures, fittings and appliances for making use of the supply of water, gas or electricity).
(c) to keep in repair and proper working order the installations in the dwellinghouse for space heating and heating water.
(1A) If a lease to which this section applies is a lease of a dwelling-house which forms part only of a building, then, subject to subsection (1B), the covenant implied by subsection (1) shall have effect as if-
(a) the reference in paragraph (a) of that subsection to the dwelling-house included a reference to any part of the building in which the lessor has an estate or interest; and
(b) any reference in paragraphs (b) and (c) of that subsection to an installation in the dwelling-house included a reference to an installation which, directly or indirectly, serves the dwelling-house and which either-
(i) forms part of any part of a building in which the lessor has an estate or interest; o
(ii) is owned by the lessor or under his control.
(IB) Nothing in subsection (1A) shall be construed as requiring the lessor to carry out any works or repairs unless the disrepair (or failure to maintain in working order) is such as to affect the lessee's enjoyment of the dwelling-house or of any common parts, as defined in section 60(1) of the Landlord and Tenant Act 1987, which the lessee, as such, is entitled to use.
(2) The covenant implied by subsection (1) ("the lessor's repairing covenant") shall not be construed as requiring the lessor-
(a) to carry out works or repairs for which the lessee is liable by virtue of his duty to use the premises in a tenant-like manner, or would be so liable but for an express covenant on his part,
(b) to rebuild or reinstate the premises in the case of destruction or damage by fire, or by tempest, flood or other inevitable accident, or
(c) to keep in repair or maintain anything which the lessee is entitled to remove from the dwelling-house.
(3) In determining the standard of repair required by the lessor's repairing covenant, regard shall be had to the age, character and prospective life of the dwelling-house and the locality in which it is situated.
(3A) In any case where-
(a) the lessor's repairing covenant has effect as mentioned in subsection (1A), and
(b) in order to comply with the covenant the lessor needs to carry out works or repairs otherwise than in, or to an installation in, the dwelling-house, and
(c) the lessor does not have a sufficient right in the part of the building or the installation concerned to enable him to carry out the required works or repairs,
then, in any proceedings relating to a failure to comply with the lessor's repairing covenant, so far as it requires the lessor to carry out the works or repairs in question, it shall be a defence for the lessor to prove that he used all reasonable endeavours to obtain, but was unable to obtain, such rights as would be adequate to enable him to carry out the works or repairs.