Thanks for your answer, dannyboy. It was very helpful.
I established that the problem was, indeed, located on the mainboard; once I removed it from its plastic casing (located lower rear of washing machine) I could see where the tracking had overheated causing the board to malfunction.
For anybody else who experiences this problem, there are a couple of replacement mainboards available for this particular machine. Which one you need is determined by the serial number (of the washing machine). The boards don't come with the necessary eprom but, assuming the board you are replacing hasn't gone up in flames you should be able to transfer the existing chip to the new board without problem. If not you will have to purchase one separately. To be on the safe side, remember to earth yourself prior to handling the board or eprom to discharge any static buildup which may adversely effect your new board.
You will need a torx T10 driver head to undo the two screws holding the board casing to the washing machine chassis. The board itself is easily extracted from the housing but you need to make a note of the location of each multipin connector prior to removal so that you put them back in the right order. Also note that, in order to remove the board you will need to detach the connector leading to the drainage pump which lies at the lower front of the machine.
Cost of new board was under £100 (and it arrived within a week) so well worth the effort of exchange.
Simon
November 2008