Yay!
An e-mail to CEO of BT has sorted it. It was a database error.
Can now order but BT's page is being shonky and only listing upto Infinity2 Not the full fat Infinity4 I want.
See, I said you would get it
It did the same for me.
Phone BT up, I think their FTTP team are on 0800 587 4787 if I am correct, then ask them what deals are available due to their product page isn't displaying Infinity 3 and 4.
I am sure they will be happy to help
Paul