Thanks for your reply.
I can't vouch for the installation being exactly plumb south as I did not fit the dish, but it was installed by a professional satellite installer. I watched most of the install and was chatting to the guy while he was doing it, he told me he was locking the dish on Thor first then 30W Hispasat followed by 28.2E Astra, which sounds not dissimilar to the method you mentioned.
Think I may just throw in the towel with this box as I plan to get a Gigablue Quad Plus anyway. It will still make a good little multi room box for the bedroom or kitchen.
Thanks for your help.