stevie21 - there are many reasons leading to the refusal of a guaranteed cheque but this is not the same thing as somebody trying to cancel a cheque.
This also from APACS;
"The Rules of the UK Domestic Cheque Guarantee Card Scheme state that a card issuer guarantees in any single transaction the payment of only one cheque taken from only one of its own cheque books for up to �50, or for up to �100 or �250 if indicated in the
hologram, provided the cheque is not drawn on the account of a Limited Company, and
i) The cheque bears the same customer name and, where printed, bank sort code, as the card.
ii) The cheque is dated with the actual date of issue.
iii) It is signed, before the expiry of the card, in the United Kingdom of Great Britain and Northern Ireland, the Channel Islands, Isle of Man, Gibraltar or on the premises of any United Kingdom Customs post located outside these territories in the presence of the
payee by the account holder.
iv) The card number is recorded on the reverse of the cheque by the payee (this requirement can only be varied by specific prior agreement of the Scheme�s
governing body).
v) The card has not been altered or defaced.
These Conditions of Use are not to be printed on the card but are to be readily accessible to any enquirer at the Issuers� branches.
If these conditions are not met the guarantee is void and cheques could be returned."