I have had a HH5 since having Infinity for 12 months. The issue i had was the HH5 was great at first, on the ethernet and wifi connection, speeds of 70 mb. The problem i had was the HH5 would NOT hold the Airplay connection for longer than one day. I stream my iTunes music from my iMac in the study to my HiFi and into the conservatory.
With the HH5 I tried various options such as Port Forwarding to overcome the problem. All to no avail.
I purchased an Airport Extreme base station, which has NOT dropped the Airplay connection once, it is rock solid. The outstanding issue is that the wifi speed has dropped to 30mb max.
The HH5 is connected to the AEBS by Cat6 cable, with the AEBS in Bridge mode. I have been talking to Apple support and they say there is no reason why there should be should a "big" drop in speed from the previous set up. I have the correct set up from their side. To date awaiting a reply from BT on why there should be a 50% drop in wifi speed than before.
Suspect the usual reply from BT "we don't support third party equipment", so not hopeful of a positive solution.