There is no defence in a court for stopping a cheque.
Irrespective of what it is for, it is classed as a "bill of exchange" this is also the same for a Direct Debit.
People who stop cheques, do at their peril, as it's an open and shut case, with them getting a CCJ.
I recently took some bitch to court for £300 plus £100 costs. She and her hubby were blown out of he water by the judge , relaying the law to them on cheques and giving then 14 days to pay.
I must say it was a sweet moment, best was they said the were prepared to negotiate a settlement, NO WAY, I punched the air on the way out, and they were behind me. Revenge is a dish best served cold.