Whats happened to my Fibre Broadband

[#1]

Tonight's been shocking don't know what the hell is going on Plusnet  speeds dropped to 2meg can hardly get on here to post this
Usual speeds were more than 50 to 60 Meg 

[#2]

Hi there,
Looks like there was a couple of drops last night but your profile is still set at 71800 on both ours and BTs sides, so there's nothing slowing you down there.
Was that with a wireless connection to the router, or wired? Also has the speed improved since?

[#3]

Hi there after reinstalling fire fox , Fire Wall , I decided to move wireless channel from auto 1 to  13 things back to normal normal now.
But I also aware there is major road works near my B.T. junction box .