HG Service Wash, or alternatively clean all the removable parts, scrub the underside of the plastic around the powder dispenser drawer to get all the mould off, then run a 90C wash with a cup of cheap biological soap powder in it, and an old towel. All the gunk will come off your machine and it will smell like new.
<preens> I will be on Superscrimpers demonstrating this exact technique probably next month. <preens again> Film crew had to stand outside in the snow while they filmed me demonstrating it in my utility room. I was not the most popular person after that!