Disregard of State Pension lump sum

I’d be very grateful if someone could identify the correct HB regulation regarding the indefinite disregarding of a deferred state pension lump sum.  It is on page 394 of CPAG but the footnote leads to the wrong place (or I’m looking in the wrong place).  Our client took advice from DWP and tells us they told her deferring taking her SRP wouldn’t affect her benefits.  She took the lump sum recently and has now been told she has exceeded the capital threshold for HB (does not get PC) and has been overpaid HB.  I hope someone can point me in the right direction.  Many thanks.

Is it not para 26AA Schedule 6 Housing Benefit (Persons who have attained the qualifying age for state pension credit) Regs 2006. ?

26AA. Where a person chooses a lump sum under section 8(2) of the Pensions
Act 2014 or in accordance with Regulations made under section 10 of the Act which
include provision corresponding or similar to section 8(2) of that Act, or fails to make
a choice, and a lump sum payment has been made, an amount equal to–
(a) except where sub-paragraph (b) applies, the amount of any payment or
payments made on account of that lump sum;
(b) the amount of that lump sum,
but only for so long as that person does not alter that choice in favour of an increase of
pension.

Para 26AA is concerned with survivors’ pensions I think, but para 26A does the same job for a lump sum based on the claimant’s personal deferred RP.  It most certainly is disregarded.

That’s what I was looking for, many many thanks!