I re-joined BT in 2017 on Unlimited Infinity - the 40/10 service at the time - as my line isn't capable of much over that and the service has been fine. So my service would have been capped at 40/10 as that's what I was paying for.
I recently renewed to Fibre 1 and one of the benefits of renewing to this, mentioned at the time, was a bit of a speed boost. Not much but anything's better than nothing.
However, my line will still only sync to 40.00Mbps download and to me it looks like my 40Mbps cap is still in place. See the Smart Hub stats attached. I phoned the helpline, who checked the speed and reset the Smart Hub etc. but although my up/down max data rate will vary due to external factors, the actual sync data rate is only ever 40.00 Mbps. Unfortunately all the helpdesk can do is check speed against my guarantee (21Mbps!!!!) - so they can't do anything about it as a fault.
Any suggestions on how I can get this cap removed now I'm paying for a higher service? OK, it's only an extra 5Mbps but it's the principle - if my line was capable of 50 I suspect I'd still only be getting 40 because of the previous service's speed cap that has not been removed.
check MYBT and see if your package has been changed from Essential to Fibre 1. then you can try options team 0800800030 if your upgrade is shown and not happened