If the cheques were guaranteed by the use of the cheque card, you'd only have one creditor (i.e. your bank).
When your cheque is guaranteed by the use of a cheque card there is 'an implied representation that you have the authority to bind the bank to honour the cheque'. If the terms of your contract with the bank make it clear that you should not use the card to guarantee cheques when you've insufficient funds, there is the possibility that you could be charged, under the Theft Act, with 'obtaining property by deception'.
See the Crown Prosecution Service website:
http://www.cps.gov.uk/legal/section8/chapter_a .html#27
Chris