Just got the HH5 but getting very slow speeds on the WIFI side 2.4 GH (around 10 mb ) was getting between 30-45 mb on the HH3. BT technical keep telling me there is an option to switch of the 5 GH in the home hub manager but for the life of me i cant see an option to switch of 5GH. Im using the HH5 in exactly the same position as was the HH3 my fibre wired ethernet speeds are fine between 70-75 meg. I am doing the speed tests for mobile, ipad, through ookla speed test. Any help advice appreciated please.

Try turning off the 'Sync with 2.4 GHz:' setting in the wireless 5GHz settings menu.
You will then be able to connect to either the 2.4 or 5GHz band as they will then be shown as two separate wi-fi networks. You can then see which is the fastest for you.

UPDATE-I clicked on forget this network on Ipad, Iphone & Samsung & re-entered passwords on all devices & am now getting speeds btween 30-45 mb. Just hope when BT-TV is activated on Tuesday it doesnt upset my fibre speeds which have been consistanly 70-75 mb for the last year. Does anyone know what speed HD channels run at ?

not much 8 or 10Mbit perhaps when you are actually watching one., i cant say i noticed an impact on my speeds because of them.

FWIW this on 5GHz on the HH5 with my PC in the next room with a brick wall between it and the router http://www.speedtest.net/result/3423073140.png the wireless card in the PC is a 450Mbit n card not an ac one.