unfortunately,thats not the case as you can cancell a bank cheque as long as it hasnt cleared,as a mate bought a car and found out it was very dodgy so he cancelled the bank cheque and gave the guy the car back

Damn I never knew that.. I thought bank cheque was pretty solid. Generally it's the accepted method of payment. If you buy a car from auction they require you to pay with bank cheque.. paying with cash isnt always a good idea as you have no proof of the transaction (only when it's a large amount of money though).