This might be of help to someone. I'm a sucker for Shipping Wars but when I sat down to watch it last night all the episodes had gone! I thought that perhaps I had hit 'delete series' instead of 'delete episode' (why the hell are those 2 options so close?!?) but with no 'deleted shows' option I had no way of checking.
I then noticed that I had 24 Episodes of 'Four in a Bed' recorded. I went in to delete them and there were my shipping wars!
So if you ever find a season or two missing from your Humax, maybe have a look around and check inside other groups of shows.