Speed test looks like this:

I've tried various different sites, and they all come up roughly the same.

And yet my router says this:

ADSL Link Downstream Upstream
Connection Speed 5536 kbps 768 kbps
Line Attenuation 49.0 db 31.5 db
Noise Margin 7.3 db 13.0 db

Anyone got any ideas why I'm getting such attrocious download speeds when my router says I've got a 5.5Mbps connection?

Any help would be really, really appreciated.