FTTC in next house but not mine?

[#1]

Hi, I posted this in the wrong forum originally, so I'm reposting:
Our so-called Broadband is terrible (600k today), so I'm desperate for an upgrade.
Our local cabinet has been upgraded to Infinity. We're about half a mile away.
The house whose garden backs onto our garden shows on the BT Infinity checker as capable of enhanced broadband. I'm guessing they can't gwet "full" Infinity is because we're quite a way from the box. Nevertheless, they can get the enhanced speed.
However, our house only shows broadband "up to" 5 megs (hahaha, I wish). We're only 50 metres away from the neighbours!
SURELY we must be able to take advantage of the upgraded box? I don't care if it's not 20 meg. Six would be a dream!
I've spent hours trying to find a number to call, or a person to appeal to. I'm at my wits' end. If anyone can help I'd be very, very grateful.

[#2]

I think you will find that your neighbour (from your description, sounds like they are in a different road) connects back to the exchange via a different cabinet/route to you...
and BT for some reason (cost) have decided not to enable your cabinet  

[#3]

I've responded to this question here: http://community.plus.net/forum/index.php/topic,97999.msg829053.html#msg829053
May be worth keeping all future responses in that thread for continuity.

[#4]

Locked in favour of http://community.plus.net/forum/index.php/topic,97999.0.html