ADSL upload speed

[#1]

Not sure if anyone can help but since Thursday/Friday last week there is no upload speed showing in the mornings.
for example:-
Using BTW speed test this morning at 9.52am it shows
download speed 2.06
upload 0.00
ping latency 0.00
If I switch the router off and then back on again the upload speed returns.
Using BTW speed test this morning at 10.01am it shows
download speed 2.25
upload 0.36
ping latency 55.25
So I'm assuming  something is happening overnight to knock it out but I don't know what.
The only router I have is a Thomson TG585 v8 software release 8.2.7.8 (issued by plusnet a few years ago). The position of the router has not changed since it was installed about 7 years ago. Nothing else in the house has changed and there is nothing on a timer in the house either.
I don't know anything about broadband so I'm at a loss to know why it's suddenly doing it. 

[#2]

Hi,
Can you please take a look at the speed issues thread - link below - and post all of the requested information?
Is the phone line quiet?  Dial 17070 option 2

Edit - corrected phone no.

[#3]

Thanks Townman for your advice but I decided to wait to see if it resolved itself (mainly as I wasn't too sure how to find the required information once I used the link).
I'm pleased to say that after a week and half the problem seems to have gone away. Not sure how or why it's gone but I'm just glad it has.

[#4]

I fear you'll find you have an intermittent line issue.  At best it will come back again no worse that you have seen.  At worse one day you'll wake up to a completely dead phone line.