Looks like the pressure switch is faulty - replace it.
Spares suppliers:
www.4directelectricals.co.uk
http://www.ukwhitegoods.co.uk
www.ukapplianceparts.com
http://www.domesticspares.co.uk
http://shop.ezee-fix.co.uk
http://www.espares.co.uk
or simply go into google and type in "washing machine spare parts" - selecting "pages from uk".
If you are familiar with ebay, there are dozens of sellers running washing machine spare parts shops at very competitive prices.
dannyboy
November 2008