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!