"How do I fix this without expensive engineers??"
You start by doing a Google search for - say - "Stoves dishwasher 600DWT E4"
That would find you things like these. Shouldn't take more than 2 minutes
http://howtomendit.com/answers.php?id=161270
http://www.ukwhitegoods.co.uk/forumsphpbb3/viewtopic.php?f=33&t=24390
http://www.justanswer.co.uk/appliance/8kxw2-stoves-s600dw-integrated-dishwasher-2-years-old.html
http://www.stoves.co.uk/customer-care/
Anon, October 2016