I think another call to Plusnet is on the cards.

Took BadBoy's advice to get iPhone to do 5Ghz. Downloads faster but still only around 57 Mbps.

So there's definitely something happening.

The engineer showed me his machine thing, clearly showing a 71 Mbps connection. The Plusnet Hub also says that. So something's not letting it give me all that speed.

iMac also reporting about 57 Mbps over wi-fi.

Are you using this site's speedtester to er, test the speed?

Finally sorted.

Plusnet needed to change the banding to match the higher speed.

The engineer said before he left, Oh, it's Plusnet, sometimes you have to call them to blah blah (can't remember what he said). We talked about it that there wasn't a cap in place, etc.

But perhaps with the engineer doing his work, it's now apparent there was a mismatch that finally showed up.

Anyway, I used bt.wholesale speedtest. 68 Mbps down now.

And here's the result from TBB:

http://www.thinkbroadband.com/speedtest/button/14763...

Thanks to everyone for their continued help. It's certainly allowed me to take an inkling and have it proven there was indeed something wrong.