So.....last week I purchased an Apple Airport Extreme (AAE) to replace (and hopefully improve upon) the HH3 supplied by BT when they installed Infinity.
By way of background, I have been predominantly using the Airplay function on the Marantz MCR603 for music, which is based in the lounge. I also have the Apple TV and Zeppelin (non air) in the main bedroom - they are connected via an optical cable (TOSLINK to mini TOSLINK) and this effectively provides music via Airplay to the Zeppelin. I use the two systems independently for the most part but also use the multiroom function at times. My music is stored on the Synology NAS in various formats (mostly FLAC).
When playing music via Airplay on both of the aforementioned I generally use the apple remote on my iPhone (if the MBP is on and not to hand) or the Synology DS Audio app on the iPhone if the MBP is not turned on or easily to hand. Apple remote picks up the NAS as a shared drive. I do also use the Music Server function on the Marantz. The latter always works without any problems. However, when using Airplay, I was experiencing 'drop off' of the two Airplay devices from the playing client (e.g. iTunes or DS Audio) after a period of inactivity or sometimes from the outset - frustrating! I assumed network issues and suspected the HH3 was the source of the problem - hence the AAE purchase.
Set up was a doddle - simply replace the HH3 with AAE and follow some the set up process in the Airport Utility app.
I am pleased to report (for those who are experiencing similar problems and considering taking a similar leap) that the AAE has improved things no end. The WLAN is now a lot more stable and I have not experienced any 'drop off' of Airplay devices with the AAE whatsoever. The new set up can also comfortably handle hi def 24bit 96khz FLAC files (constantly buffering with HH3) - I only have a few of these, however.
Internet browsing is not noticeably different either way (already lightning quick on HH3), upload time to Synology NAS appears marginally quicker and connections to other Wi-Fi devices (e.g. wireless printer) seem more stable.
There are obviously other suitable upgrade alternatives to the AAE (before the Apple haters pipe up) which I am sure would have done the same job (if not better). Hopefully if there are other users in a not too dissimilar boat this post will be of use to them.