Having experienced pretty much identical issues as you’ve been having (outwith the speed drop) I’m hoping I can provide you with a potential solution.
In my case my problems started soon after July 15th when my HH5A received its first update in 2 years. Prior to it my hub would reboot once every 14 days pretty much like clockwork. After the update (which you got on July 14th – does that coincide with when you started noticing the issue by any chance??) my router would lose connection from anywhere between 6 – 48 hours and sometimes 2 or 3 times in a day. I had more disconnects in 7 weeks than I’d had in 7 months!!! I knew when a disconnect was coming as my downstream line noise would go into negative figures and then then low and behold the orange light would be flashing & no more internet. Sound familiar? Luckily for me my speeds were never affected but it was still annoying when I’d lose my internet connection midway through watching Netflix, etc.
One of the mods on here kindly looked into the issue but due to the randomness of the disconnects no solution was forthcoming.
I however, borrowed my sisters old & unused HH5B and plugged that in to see what would happen. That was around 4 weeks ago and after it updated its software I’ve only had one reboot – the regular ‘14 days’ one. My line noise figures also remain pretty much constantly the same.
So in my case and I’ll be diplomatic here, the software update my HH5A received made my router ‘incompatible’ with my line. Obviously there is no guarantee our problems are identical but the similarities are striking and if you can try a different router (just not another 5A!!) it may save you tearing out too much more hair!! Hopefully this helps and I guess on the off chance it makes no difference it’s one thing to rule out of further fault finding.
@kencar - Sounds pretty much spot on - I called BT on the 19th July reporting a fault...
I'm Not Alone!!
Had to then wait till the 15th September for my Line speed to decrease sufficiently for them to organise an engineer.. Annoyingly my line speed stayed at 53.17Mbps for about a month, which was above my guaranteed minimum of 53Mbps.(deep breaths were needed during my phone conversations!). Finally all the constant disconnects eventually worked the DSLAM up enough to drop my line speed to 48Mbps...
So I have spoken to BT, who have said that yes 7 disconnects within 24 hours is a sign there is a problem with the hub... which is what I've been trying to tell them since July - they kept on relating it back to speed - which as you mentioned doesn't really matter as long as you can actually get 'On-Line' in the first place.
Replacement Hub on the way, probably Monday/Tuesday now though... Maybe I'll just plug my Draytek modem back in - if they send me another HH5A..
Thank you for answering! I'll let you know if the issue is resolved! With all this CrossTalk chatter I was about to get Fibre laid down to the exchange!