if you disconnect the Boost so Sonos is not connect / working do the speeds increase? 

Hi again

I’ve stripped it all down and rebuilt progressively checking speeds with SpeedTest. (Ookia) 

I don’t really notice any difference with / without Boost.

But BT say it is the speed at the access point that matters and that is reported at 148Mb/s and when they saw Sonos on the network said it is all due to that system saturating the system, yet it generates its own mesh off the router port and all my Sonos devices are attached to that.

with nothing connected wired or wireless except MacBook pro @1m away SpeedTest reports 90-100Mbps

BT are full of BS, Ookla used be my goto speed test but over the past year for me at least its not consistent. Just tested with Ookla using the iPad it show 75Mbps, fast.com gives 150Mbps and the Ofcom checker 94.7Mbps so three different values, probably none are exact.

Those are the sort of speeds I would expect unless literally ontop of the Smart Hub. I get 142Mbps on my hub day in day out via Ethernet.

EDIT I don't use the wifi in the Smart Hub but use Plume SuperPods, Mac mini using the Ookla app gives me 115Mbps and I am about 20ft away through two stud walls in a new build.

Forgot to ask are you connecting using 5GHz? 

wired boost to router and then according to BT smart hub they are all under this port.

so i’m not sure, they don’t appear under wireless 

Sorry not Sonos but your devices which are not as fast as you would like.

They wouldn’t. All the Sonos devices connect through the Boost, and hence its wired router connection.

Thank you to everyone  who has highlighted this problem.  I have spent 7 days trying to sort my problem out, I have 4 Play Ones.  I upgraded to fibre broadband with a  BT Smart 2 Hub and my app on my phone and Mac can’t find the Sonos network.  I have reset it so many times I’m giving up the will to live. I have an Amazon Show and the only way I can use my Sonos speakers is to ask Alexa to play something. As my Sonos speakers don't have Alexa it means I have to be in the same room as my Show to change the media. I was so relieved when I found this thread.  I hope they sort it quickly.  

Note that there is an extensive BT smart hub 2 thread already here.

Sorry, I’m new to this forum. I realised my mistake as soon as I’d posted it but then couldn’t see how to edit/delete!!!‍♀️

Not to worry! Mostly that was for others that come along on this thread. And there are already at least a dozen separate threads, so pushing others who are experiencing this same issue to one place may help. At least, I hope ;)

Welcome to the madhouse!