Helios - you are right!!
I inadvertantly left the screw in bit out after changing the date a few months back - and then went and sat in a sauna - DOH!
Despite trying to dry out the interior in the (airing cupboard!) it had to go back for a good service.
Total time = 10 weeks
Cost = £190
It came back absolutely gleaming and dry as a whistle inside.
When I sell it I can now say FSH in the advert!