The published version includes the obligation of a landlord to actually produce a summary. That section however while enacted, is not in force until a commencement order is issued.
The right still exists but only on request by a leaseholder or the Secretary of a recognised tenants association.
The text of the Act as currently in force is set out below.
Full credit to be given to Jeffrey Shaw and his Secretary for producing this.

21. Request for summary of relevant costs

(1) A tenant may require the landlord in writing to supply him with a written summary of the costs incurred;
(a) if the relevant accounts are made up for periods of twelve months, in the last such period ending not later than the date of the request, or
(b) if the accounts are not so made up, in the period of twelve months ending with the date of the request,
and which are relevant costs in relation to the service charges payable or demanded as payable in that or any other period.

(2) If the tenant is represented by a recognised tenants’ association and he consents, the request may be made by the secretary of the association instead of by the tenant and may then be for the supply of the summary to the secretary.

(3) A request is duly served on the landlord if it is served on;
(a) an agent of the landlord named as such in the rent book or similar document, or
(b) the person who receives the rent on behalf of the landlord;
and a person on whom a request is so served shall forward it as soon as may be to the landlord.

(4) The landlord shall comply with the request within one month of the request or within six months of the end of the period referred to in subsection (1)(a) or (b) whichever is the later.

(5) The summary shall state whether any of the costs relate to works in respect of which a grant has been or is to be paid under section 523 of the Housing Act 1985 (assistance for provision of separate service pipe for water supply) or any provision of Part I of the Housing Grants, Construction and Regeneration Act 1996 (grants, etc for renewal of private sector housing) or any corresponding earlier enactment, and set out the costs in a way showing how they have been or will be reflected in demands for services charges and, in addition, shall summarise each of the following items, namely:
(a) any of the costs in respect of which no demand for payment was received by the landlord within the period referred to in subsection (1)(a) or (b).
(b) any of the costs in respect of which:
(i) a demand for payment was so received, but
(ii) no payment was made by the landlord within that period, and
(a) any of the costs in respect of which:
(i) a demand for payment was so received, and
(ii) payment was made by the landlord within that period,
and specify the aggregate of any amounts received by the landlord down to the end of that period on account of service charges in respect of relevant dwellings and still standing to the credit of the tenants of those dwellings at the end of that period.

(5A) In subsection (5) “relevant dwelling” means a dwelling whose tenant is either:
(a) the person by or with the consent of whom the request was made, or
(b) a person whose obligations under the terms of his lease as regards contributing to relevant costs relate to the same costs as the corresponding obligations of the person mentioned in paragraph (a) above relate to.

(5B) The summary shall state whether any of the costs relate to works which are included in the external works specified in a group repair scheme, within the meaning of Chapter II of Pt I of the Housing Grants, Construction and Regeneration Act 1996 or any corresponding earlier enactment, in which the landlord participated or is participating as an assisted participant.

(6) If the service charges in relation to which the costs are relevant costs as mentioned in subsection (1) are payable by the tenants of more than four dwellings, the summary shall be certified by a qualified accountant as:
(a) in his opinion a fair summary complying with the requirements of subsection (5), and
(b) being sufficiently supported by accounts, receipts and other documents which have been produced to him.


Update 19 February 2014 :-

The Court of Appeal has decided that neither of these provisions can be enforced by a tenant in proceedings in the civil courts in Morshead Mansions http://www.bailii.org/ew/cases/EWCA/Civ/2014/96.html.

What this means that while it is a statutory obligation and a statutory right, the Courts have declared that they are not willing to enforce the law, and that proceedings are only available in an action taken by your local Council. They will in most cases decline to do so.