I have just got a new computer that supports ac wireless and my HH5 connects at 65Mbs fairly constantly. The Ethernet port gives me about 62Mbs. Mind you, the kit is all in the same room. So I got the new 11ac dongle from the BT shop and plugged it into my wife's laptop in the next room. 60Mbs, so not bad. She was getting 40ish with a conventional 5G dongle. I've walked around the house and tried the laptops in several rooms on different floors (we only have two, so not a big mansion) and the 11ac connections give 60+Mbs everywhere. The connection from the router to laptops is 433Mbs now. Might be worth considering if you get lots of buffering on iPlayer etc. or big variations room to room. I see that the BT price for a HH5 in the shop is £129 but it seems to be particularly good over 11ac. I got mine free by signing an 18 month contract when I ditched my HH3. The BT line checker tells me to expect 62Mbs maximum so I'm pretty pleased.
Dell Studio1558 with Win7 Home Premium
HP Pavilion netbook Win8 8GB RAM
IE11 and Live Mail
BT Infinity 2 via HH5
(Virgin 150Mbs as backup)