As has been posted on here many times already, the upgrade to Plus has reset DLM. Give it 14 days for G.INP to be re-invoked and your speed should be back up.
Any problem after then get back.
Ok so after roperting the issue on here I decided to just call BT and make them aware of the issue I was having so they had it on record. They did try "Tests" which seemed to make my connection worse for a while so advised they would send out an Engineer. I advised that I would rather monitor the connection to see if it improves over the 14 days. I did advise them of G.inp and DLM but they didn't know what I was talking about.
Last night I checked my connection and it had been online for 13 days and so many hours, Tonight I checked it and its now back to 0 days and 18 hours :(. My connection is still lower than minimum. Is there anything else I can do or ask BT to help with?
Strangely tonight I also noticed my mobile wasn't on the wifi and my SSID wasn't showing. I browsed to the router IP to find out that the SSID had changed to Broadcom_02263820 and a completely different WiFi password. Any clue why this has happened?
can you repost the router stats please
BT Hub 6A
1 Days, 10 Hours 59 Minutes 59 Seconds
12.18 Mbps / 45.37 Mbps
Maximum data rate:
12175 / 55271
6.1 dB / 6.5 dB
VPI / VCI:
Data sent / received:
23191 MB Uploaded / 8291 MB Downloaded
2.4 GHz wireless network name:
2.4 GHz wireless channel:
Smart (Channel 11)
5 GHz wireless network name:
5 GHz wireless channel:
Smart (Channel 36)