We have had FTTP since December 2017 and I have to say that we have received an absolutely flawless service from BT since that time. A few months back we upgraded to "Full Fibre 900 with BT Halo 2" and initially speeds were as advertised.
However over the last couple of months download speeds have been around (actually slightly less) than the minimum guaranteed download speed of 455 Mbps. Generally download speeds have been 425Mbps-435Mbps. Interestingly upload speeds have always been bang on (or even slightly better) than the normal as advertised.
I can't seem to determine how to report this as I end up in a loop on the website which tends to end up pointing me to these community forums. When I look at "My Products" on my account page, it lists the normal and minimum speeds with a button to "Send email" but this appears to do nothing.
It's not the biggest issue in the grand scheme of things nevertheless we are not getting what we are paying for and neither it would seem are many others on the same estate where the FTTP was installed. It seems that most are getting around the minimum rather than the normal which seems to be too much of a coincidence.
So, other than posting here, how can this be properly reported and investigated?
Presumably, you're getting these speeds on a wired connection, rather than over WiFi?
I know BT guarantee around 450 as a minimum but if your neighbours are experiencing the same issue, I wonder if this could be contention, although I was assured by the Openreach engineer who installed ours, that this shouldn't be the case.
Have you tried contacting Openreach directly to see what they say?
If not, hopefully one of the mods here will be able to offer you some help.
Good luck with that one. You are not an Openreach customer, your ISP is.