Will post the whole sordid details when I get a few more round tuits.
However, I did it!
Took a little while to find the satellite, I tried the idea of setting it up on the workmate in the garden, but got nowhere. Having read a bit more, I think I probably picked up Eurobird or somesuch. I was getting loads of signal strength, but no Signal Quality, Lock, etc.
I gave up and fixed the dish to the wall and had another go. I lucked out on my second sweep, can only have taken about 5-10 mins of searching.
Thanks for all the advice guys!