No change in speed with Fibre Extra

[#1]

I upgraded to Unlimited Fibre Extra on the 17th March and have seen no improvement in speed and during the day service 

is often falls below the Minimum Guaranteed Speed: 27.3Mbps.

I ran some tests with: https://speedtest.btwholesale.com  after midnight:

- Download Speed (Mbps): 29.05
- Upload Speed (Mbps) : 8.71
- Ping Latency (ms): 13

From my account:- Product: Unlimited Fibre Extra
- Minimum Guaranteed Speed: 27.3Mbps
- Current Line Speed (Download): 80Mbps
- Estimated speeds are 31 - 44Mbps.

I have never had a speed in excess of 30Mbps even in the middle of the night and the the IP profile on the BT site would suggest no upgrade has been performed.

[#2]

The further diagnostics were as follows:

1. Downstream Test: -provides background information.

Download Speed 23.03 Mbps
0 Mbps - 30.88 Mbps Max Achievable Speed

Download speed achieved during the test was - 23.03 Mbps
For your connection, the acceptable range of speedsis 21.61 Mbps-30.88 Mbps
Additional Information:
IP Profile for your line is - 30.88 Mbps

2. Upstream Test: -provides background information.

Upload Speed 16.38 Mbps
0 Mbps - 20 Mbps Max Achievable Speed

Upload speed achieved during the test was - 16.38Mbps
Additional Information:
Upstream Rate IP profile on your line is - 20 Mbps