I thought I'd create a generic thread to cover off the issues being encountered on the 2015 Bravia Android TVs. I've listed my issues below with fixes / workarounds and responses from support. All comments and solutions welcome!

1) Hot Swap HDMI doesn't work - manifested by no input on HDMI channels 2, 3 and 4 on the KD-49X8305C. Workaround - reset the TV, either by holding down the remote power button for 5 seconds or by switching the TV off at the wall and then back on again. Further details on this thread: https://community.sony.co.uk/t5/televisions/kd-49x8305c-hdmi-2-3-4-inputs-not-working/td-p/1944435

2) HDD Recording doesn't work - error message states a system update is required but none is available when checking. Hopefully this will be fixed soon by a firmware update.

3) Netflix App doesn't work - this seems like the app has been deliberately disabled. So far a support case has only recommended that a factory reset be performed (took two days to get to that cracking piece of advice.....), with no improvement as a result. A temporary (albeit for advanced users only) workaround is provided by MikeLothian on this thread - https://community.sony.co.uk/t5/televisions/netflix-support-for-kd55x8509c-android-tv/td-p/1945360 

4) Sound lag and performance issues after the TV (KD-49X8305C) has been on standby for a while - manifested for me as stuttering and sound / picture sync issues in all apps (youtube, amazon instant video etc) and HDMI sources (PS4, seperate YouView box etc). Hopefully this will be fixed in a firmware update, at the moment workarounds involve either changing channels to get the sync to work or in my case having to turn the TV off and then on again at the socket.

As stated previously, all comments welcome. Personally I'm willing to give Sony a couple of weeks to fix this, but if it's not done soon I'll be sending my new TV back for a refund as it's not really fit for purpose.