The act of proceedings being declared void due to lack of Queen's consent being signified has only happened once, and never during the reign of Queen Elizabeth II, but for Royal consent in general, this has happened at least three times according to a Parliamentary pamphlet intended for members of the Office of the Parliamentary Counsel entitled Queen's or Prince's Consent:
7.5 Proceedings on a bill have been declared void because of a failure, through inadvertence, to signify Queen’s consent at the
49.CJ (1852) 157; CJ (1911) 388; CJ (1948-49) 323
Most recently, then, we look to page 323 of the Commons Journal for 1948-49, which shows:
Ordered, That the Proceedings on the Third Reading of the National
Parks and Access to Bill, the
Countryside Bill yesterday be null and void, and that the Bill be read
the third time to-morrow. (Mr. Whiteley.)
This appears to have gone ahead without King's consent being signified. If we look to the record in Hansard for this date, this is confirmed:
The Deputy-Chairman of Ways and Means (Mr. Bowles)
I wish to tell you, Mr. Speaker, that on Third Reading of the National
Parks Bill last night, by inadvertence, I failed to call for the
King's Consent to be signified. I wish to express my regret.
The Parliamentary Secretary to the Treasury (Mr. William Whiteley)
I beg to move,
"That the proceedings on the Third Reading of the National Parks and
Access to the Countryside Bill on 19th July, 1949, be null and void
and that the Bill be read the Third time tomorrow."
Question put, and agreed to.
The next day, King's Consent was given.
The next most recent instance is in 1911. On page 388 of the Commons Journal, we see:
Ordered, That the Proceedings on the Third Reading of the National Gallery and Saint James's Park Bill [Lords], upon the 4th day of this
instant August, be null and void, and that the Bill be read the third
time to-morrow. - (Mr. Dudley Ward.)
There seems to have been a bit of confusion and aggravation here - it doesn't seem to have been relayed at this point to the House why the Bill was being declared null and void. We see later on in Hansard when the third reading was again proposed, there was significant confusion and an attempt to adjourn the debate:
Sir F. BANBURY
I challenge hon. Members below the Gangway to say why the proceedings
were declared null and void. I challenge anyone to get up and give an
intelligent explanation of that. I say this is a farce, and the House
ought not to proceed with the discussion of the Bill until an
explanation is given why the proceedings on the Third Reading were
declared null and void. If I cannot get any explanation, I will, under
the circumstances, move "That the Debate be now adjourned."
Mr. DUDLEY WARD
I think the House will agree with me that I have had very little
opportunity so far of getting in a word at all. This Bill deals with
Crown property, and certain forms have to be gone through before a
Bill dealing with Crown property can become law. The Royal Assent has
to be given, and the House has to be notified that Royal Assent has
been given. Last Friday I forgot to tell the House that the Royal
Assent had to be given, or to have it signified to the House that it
had been given. In those circumstances it became necessary to declare
the proceeding on the Third Reading null and void. I now ask the House
to read the Bill a third time.
Finally, we look to the Commons Journal for 1852. Unfortunately, I think the reference here is wrong - I was able to find what I think should be the correct reference on page 578 rather than 157:
Notice being taken, That Drummond's (Duke de Melfort's) Restitution
Bill had been read the first time; and that Her Majesty's Consent to
the same had not been given;
Ordered, That the Proceedings of the
House of the 13th day of this instant June, in relation to the first
reading of the said Bill, be null and void. And a Motion being made,
That the Bill be now read the first time ;
Sir William Molesworth,
by Her Majesty's Command, acquainted the House, That Her Majesty,
having been informed of the purport of the Bill, gives Her Consent, as
far as Her Majesty's interest is concerned, that the House may do
therein as they shall think fit.
Ordered, That the Bill be now read
the first time: The Bill was accordingly read the first time; and
ordered to be read a second time.
Ordered, That the Bill be now read a
second time:- The Bill was accordingly read a second time; and
committed to a Select Committee.
However, the record of this sitting in Hansard does not include any reference to this, probably because the digitised archive starts to get a bit dodgy before 1900. It should be noted that this case is the only known case of proceedings being declared void due to a lack of Queen's Consent - as it occurred under Queen Victoria. The other occasions occurred under King George V and King George VI.