Unlimited Fibre Extra - very disappointing download speeds

[#1]

I have noticed over the last 3-4 months my download speeds have decreased somewhat (tested at different times of the day from the master socket). I am consistently getting between 48-50Mb which is slightly above the Minimum Guaranteed Speed of 46.5Mb. When I first signed up I had really good download speeds however the speed has definitely degraded over time. I'm am not getting anywhere near the average of  66Mb, let alone near to the peak speeds promised.  I'm also not too far away from the exchange cabinet (near the centre of a town). Don't really want to change provider as have been with plusnet for nearly 8 years. 

[#2]

Here are the results of the BTWholesale speed test

Basic Performance Test - Time Stamp Latency Download Upload Friday 1 May 2020 | 17:33:30 22 Ms 47.63 Mbps 18.52 Mbps

Advanced Performance Test -

Download Test Download speed achieved during the test was 47.63 Mbps For your connection, the acceptable range of speeds is 40-53.61 Mbps Your DSL Connection Rate: 0 Mbps(DOWN-STREAM),0 Mbps(UP-STREAM) For your connection, the maximum achievable download speed is 53.61 Mbps IP Profile for your line is 53.61 Mbps

Upload Test Upload speed achieved during the test was 18.52 Mbps For your connection, the maximum achievable upload speed is 20 Mbps IP Profile for your line is 20 Mbps Summary Advanced Performance Test - Result Message We were unable to identify any performance problem with your service at this time.It is possible that any problem you are currently, or had previously experienced may have been caused by traffic congestion on the Internet or by the server you were accessing responding slowly.If you continue to encounter a problem with a specific server, please contact the administrator of that server in

[#3]

@ablearcher Together with our network partners at Openreach we are prioritising customers who don’t have a phone line or broadband connection, meaning there might be a delay in Speed Faults being fixed. In the meantime, please raise your speed fault online at http://faults.plus.net.