Slow Fibre Download Speed

[#1]

Internet was installed roughly one month ago. Test have been done on installation day and BT guy said download speed is 38 upload is 9 megabits.

No problems when router arrived and installed. Speed was very similar to one give by BT guy. 3 or 4 days ago I've notice big download speed drop. It was 3 - 5 megabits in various speed test sites.

Today I have tried BT Wholesale Broadband Performance Test. Upload speed as it suppose to be close to 9 megabits. Download speed was 2.4 megabits.

Later on I have disabled wireless option on the router. Followed all steps at provided by BT test. Upload speed staid as it suppose to be close to 9 megabits. Download speed was slightly better, but still it was only 10.47.

Tested with desktop and laptop connected via cable directly to router.

Plusnet needs to have a look at this issue ASAP as I am not happy with service. Too many times had to contact customer service already and now speed issue.

Independent speed test websites at the moment shows 2.4, 2.3 megabits speed, while BT shows 10 megabits.

[#2]

BT Wholesale Performance Test

Big difference between BT and Speedtest.net

[#3]

@linasm you have what's called a 'hot VLAN' which means that capacity is high at your cab so a large portion of the connections to it are going to have diminished speeds until capacity is freed up. 

You started raising this fault on the account yesterday. I've finished raising that for you. It will automatically be sent to Openreach and we should then receive a date for resolution of the problem for you. 

[#4]

Thanks for having a look at my case.
You are right. I have done some speed measurements on speedtest.net. After midnight download speed was approximately 30 megabits, 9 am 37 megabits, 4.30 pm 36 megabits, 5.30 pm 30 megabits, 6.45 pm 8 megabits. Possibly line will be much slower later on.
Hope this issue will be dealth with soon. Thanks in advance.