Is it a new build? With any luck, it’s just the databases that haven’t been updated properly. The fact other house numbers nearby don’t show the issue makes it sound like some sort of admin error rather than an actual fault.
I ended up having to buy a 4G router and an unlimited data SIM with 3 when I moved home. Only 4Mbps ADSL available, when most of the development had fibre. Very frustrating! It went on for several years before YouFibre, a small, independent provider turned up and put their own fibre into everyone’s properties. I now have 1Gbps full fibre and it’s amazing
I got a SIM-only deal and bought my own router - a TP-Link TL-MR6400. I used it with Google Wi-Fi points around the house. It was incredible when I first got it - I went from 4Mbps ADSL to between 40 and 60Mbps download. In my case, after a couple of years, everyone in my area realised they could get a better connection via Three and it really affected speeds.
I went for the :
TP-Link AC1200 4G+ Cat6 Wireless Dual Band Gigabit Router, 4G Network SIM Slot Unlocked, with MU-MIMO technology, No Configuration required, Guest Network & Parental Control, UK Plug (Archer MR500) https://amzn.eu/d/i3KSEJz
Also ordered an unlimited SMARTY data sim … let’s see how it goes next week when I move in.