ADSL Status Connected
Data Rate Down/Up 8128Kb/448Kb
WAN MAC address 00-11-50-84-1D-3B
Connection Type PPPoA
Yay!
This is the good bit. You don't have ADSL2 or FTTC available to you, there is no LLU on your exchange.
Therefore, your 8 meg sync is as fast as it is getting right now.
However, from what you've said, you're not seeing 8meg!
Given that you can't improve on the sync however, there is no need to worry further about house wiring, faults, noise, etc.
What we need to do now is get you to that sync speed.
The fact that there is no LLU provision at your (tiny!) telephone exchange means that providers that usually use LLU will either not serve you at all, or will put you on their non-preferred network, which tends to be a recipe for slow speeds.
The lack of choice at your exchange means some providers will charge you more per month (e.g. plusnet).
Before we get too far into which ISP though, it's worth at least considering other things.
You say this speedtest was on an iPad via wifi. I'd expect Wifi to get more than 8meg anyway, unless it's an 802.11b router or an 802.11g router with poor signal, but do you have any wired devices you could test?
Your router says 5 devices are attached. Can you account for all 5? Is it possible your neighbor is using your Wifi, or your kids are downloading films/music from bittorrent?