Quickstep? Slow slow - occasionally quick - slow

[#1]

Am on a premium phone line service and the OX15 Bloxham exchange is supposed to give me 18MBs and should apparently not suffer slowdown at any time of day.
The reality is I'm unable to update websites as the speed is often slow slow I lose the link - and my amendments.
I have a state of the art dual band Netgear router which WAS  working at OK speeds and still is for internal networking.
Now I feel lucky if I exceed 2MB in the evening.  Just tested on the BT spoeedchecker:
Download 2.3
Upload 0.8
Latency 169
I'm paying £17.99 /month for a £3.99 service! 
It's a hassle moving but it's getting to be even more of a hassle staying!

[#2]

If it's just affecting your throughput and latency during evening peak hours, there is a fault affecting many Plusnet customers. Not sure if you are aware of it. More details:
http://community.plus.net/forum/index.php/topic,111170.0.html
and
http://www.plus.net/supportpages.html?a=2&support_action=messages&ispservice_id=adsldial

[#3]

Hi there,
Since you posted have your speeds improved?

[#4]

jkgplus - Welcome to the forum and sorry to hear about the problem. I'm trying to track down the cause of the problem that's affecting some of our customers so want to try and understand if the problem you're seeing is related or whether it's something different? Do you know when the problem started and if it happens every evening? Are you speeds normal outside of the evening or slow all the time? If you disconnect/reconnect or reboot your router does the problem go away (at least temporarily)?

[#5]

No its's not just the evenings it's been all day that I've been taking an hour to do what should take me 10 minutes waiting for data transfer.
I have tried rebooting the router to little effect.  I am on a fixed IP address  80.229.162.125
Here's results from a few occasions tonight.
Download  upload      latency
1.96            1.58          1,87
0.67            0.64          0.76
0.62            0.63          92.6
1.28            0.62          93.5
I really am going to have to swap  provider if this doesn't improve.  People expect me to update websites for them in minutes but it's taking me hours  and I'm losing work in the process.
Not a happy bunny!