Heavy packet loss on FTTC since 22nd March

[#1]

I switched to plusnet FTTC on the 5th Jan 2015. Ever since then I have had instances where my web browser will intermittently say page cannot be displayed.  I eventually purchased a combined modem / router Billion 8800NL so that I could try and get some view of what was happening,  as the modem supplied by BT  would not let me monitor anything.  On running router stats lite against this I could see that I was getting significant packet loss. I then obtained a copy of pingplotter and this shows that I am getting packet loss varying between 25 and 40% most of the time.
I have had several BT engineers out (5 if I remember correctly) but the problem is still on-going and the packet loss has not reduced. Can anyone help get a handle on this problem please. I am now almost 7 weeks into this with no progress at all. I feel the problem needs more focus from PlusNet but it doesn't seem possible to escalate the call anywhere. The call loggers will not allow me to speak to a manger which I find most frustrating. I have attached a sample image from pingplotter to give some view of the problem

[#2]

Hi rayatkin,
Most people around here use TBB graphs, have a mooch.. http://www.thinkbroadband.com/ping
Edit added Plusnet Users

[#3]

This is only applicable if you have a static IP address. Not everybody has

Quote

Can you monitor my connection if I have a dynamic IP? We can only monitor your line if you have a static IP address as we are not able to track changes to your IP address at the moment. We will look at adding this functionality in a future version.

[#4]

Quote from: Chris64

This is only applicable if you have a static IP address. Not everybody has

You can use it to monitor if you have a dynamic IP address. If you lose connection though, it will  just show a red band from then onwards as it cannot see the new IP address when you reconnect.
If the connection itself is stable, it will still give a lot of useful info.