Are you sure your line is 1.3km to the cabinet not the exchange?
Certain! I'm much further from the exchange, probably about 6.5km cable length and a lot of it's aluminium on the E side (72dB attenuation on ADSL2+). BT (and KN) told me the line length when they were installing the poles, etc. I also got the engineers to confirm it when they were testing, and I checked it myself (Google Maps, phone with GPS, etc.). There's only one available path from the cabinet to my premises. The cable is 0.9mm in areas and 0.6mm in others, but it still doesn't really make up for estimates like that.
How accurate are those estimates supposed to be? My neighbour up the road is getting estimates in the mid 60s down to 40 something and they'd be 1.5km away, so it seems to be affecting more than just me. My neighbour closer (about 1km) always got estimates in the region of 73 down to 50 something. None of us are on the same DP.
The only possible explanation, however unusual, is that it actualy isn't 0.9mm, and something thicker (I'm told reliably that that's never been seen). I've completely ruled out a shorter route to the cabinet, there just isn't one, and even the old potential one that might've been there would've only been 50m shorter, but I'm told under no uncertain terms that the line does not route that way (the road was closed in the 60s). We'll see what speeds the new line yields! I suspect the checker's just being daft.
Unfortunately the new PN router is a re-badged HH5A with some slight firmware changes (Removal of BT WiFi).
Looks like the Hub One will be lying in a box! Thanks for the info.