I'm Getting Very Poor Download Speeds since Openreach Spotted outside - related?

[#1]

I have been an Unlimited Fibre customer for well over a year and until very recently (and since the start of the COVID 19 lockdown) my download speeds have been acceptably between 50 and 70 Mb.  A couple of days ago we noticed Openreach engineers working at the end of our drive.  They assembled control barriers around the area they were working so we assume this was more than an inspection.  Since then we have only been getting around 10 Mb download (see attached BT Performance Test report).

Curiously, when I log on to the PlusNet router it reports Downstream: 72.88 Mbps and Upstream: 19.98 Mbps.

Can anyone advise:

1) how I can find out if there is a fault somewhere;

2) how I can find out what Openreach where doing

I am aware, and accept, that during the current lockdown I should expect some degradation of service while everyone is working at home, but from 50 to 10 Mb seems a bit excessive?

Thanks in Advance

Tim

[#2]

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 faults.plus.net.