Hi @Vinnie650
1. If you connect to the SH2 with a Cat6 cable *and nothing else is connected (wired or wireless)* you should get the advertised speed (900 Mb/s) - I certainly do.
2. That suggests your WiFi is capable of 150 Mb/s - it's unlikely to be capable of 900 Mb/s. You *might* be able to get 3 or more devices simultaneously doing 150 Mb/s, or maybe one device doing 250 Mb/s - WiFi is too difficult to predict, and very little to do with your internet connection spped. With my 900 Mb/s FTTP connection and SH2 I get between 200 Mb/s and 350 Mb/s on various devices.
3. The only guaranteed speed is between the BT network and the SH2 - because those are the only things in BT's control. Even then, the BT "speed guarantee" just means they'll give you £20 if they can't get a speed test to show you the promised speed once in a 30-day period (https://www.bt.com/help/broadband/what-is-bt-s-stay-fast-guarantee-)
4. You can be certain that you're getting a fibre connection at 1Gb/s (on the FTTP 900 package) - if you don't then there's a fault. You can be reasonably certain that if the network is not too busy you will be able to sustain the 900 Mb/s download for at least short peiods of time. And you can check this with something like speedtest.net or fast.com.
5. This is a way for pretty much all telecom providers to deliver fibre to homes. Running individual fibre connections between an exchange and every home would be ridiculously expensive and unnecessary - so FTTP gives you a branch on a shared fibre. On GPON (as currently deployed by Openreach and used by BT et al) this gives ~2.5Gb/s downstream shared between ~30 subscribers. If everyone else is idle, you can use your 900 Mb/s fully; if everyone is busy, you get on average ~ 80Mb/s each.
