Dropped to around 2Mb/s for a few days now.............

[#1]

After a period of relative stability, my speed had dropped dramatically over the last several days. Streaming is impossible due to regular buffering.
BT Wholesale test shows:
1. Best Effort Test:  -provides background information.
Download  Speed
1.56 Mbps

Download speed achieved during the test was - 1.56 Mbps
For your connection, the acceptable range of speeds is 4 Mbps-21 Mbps.
IP Profile for your line is - 8.21 Mbps
2. Upstream Test:  -provides background information.
Upload Speed
0.25 Mbps

I was intending to sit it out hoping that things might improve - but they haven't.
Can Plusnet do a few diagnostics to indicate what's happened?

[#2]

Absolutely no issues I can find, your line is still profiled at 8.2Mb/s and the connection has been good and stable.
Are you still seeing problems?

[#3]

Thanks for getting back to me so quickly. Speed still poor.
Latest test:
1. Best Effort Test:  -provides background information.
Download  Speed
1.58 Mbps

0 Mbps 21 Mbps
Max Achievable Speed
Download speedachieved during the test was - 1.58 Mbps
For your connection, the acceptable range of speeds is 4 Mbps-21 Mbps.
IP Profile for your line is - 8.21 Mbps
2. Upstream Test:  -provides background information.
Upload Speed
0.28 Mbps

0 Mbps 0.45 Mbps
Max Achievable Speed

[#4]

Can you run through the faults checker for us please, https://faults.plus.net