Hi guys, I happen to have a similar issue like lizzie8: Sky works great, new Freesat box hits the wall with no signal (or sometimes with a flash of signal in the Wizard stage which disappears in a second; sometimes I am left with LNB connected but NO SIGNAL!).
I checked CBS Action, and Sky box said no signal. I tried adding the channel you mentioned, but as soon as I do it, it can't finds any channel and after that I get no channel at all where I could! Then I have to restart the Sky box to be able to get BBC etc.
What you said seems strange: if Freesat states I can use my existing dish, I really should! My dish was installed last year. But because there are some tree branches in between, I get ~75% signal strength but around 30-40% signal quality on Sky (and like so when Humax box flashes the bars in a second with GOOD strength and BAD quality). In windy conditions HD channels get distorted but otherwise no problems.
I thought my Humax box is faulty but the replacement box I got from Amazon shows the same symptoms.
Will probably have to wait till Monday to speak to Humax tech support.