Thank-you, thank-you, thank-you
So I ordered the part from this site (£20.50) and it took two days to arrive.
I followed the instructions from Jim (plus the tip from the earlier thread about lying it face down to avoid loosing screws and also only taking one out completely) and it took about 15 minutes to swap it over.
A bit tricky extracting the relay out into the open but once out swapped the cables like for like with the new one, put it back together and it works! My first ever appliance repair and no cuts or other injuries.
My wife is seriously impressed!
Thanks to everyone who helped out.