ADSL2 connection dropping since August

[#1]

Hi there,
Our line was switched from ADSL to ADSL2 back around August time. To begin with our (then) current router, a Netgear DG384GT, couldn't even connect despite having the latest firmware which enabled ADSL2. We had a spare Edimax AR-7084gA router laying around which we swapped for the Netgear and everything connected fine on ADSL2 and after a few days the speed settled and everything looked okay. However since then, whenever a high demand is put through the line/router, the connection just drops (for example, downloading a song through iTunes or trying to stream a youtube video). It just seems as though it can't handle the speed and just cuts out. We just have to reboot the router and start again.
Our speed is currently okay:

However it seems to almost 'pulse' down the line, jumping from about 2/3 mbps to 9mbps and back again, see below:

Does this sound like a router issue, or should we request to be switched back to ADSL where we were receiving an absolutely faultless 6-7mbps continously?
Unfortunately we don't have another spare router and don't want to buy another one, especially this side of christmas.
This is our exchange (which is about 1-2 miles away) if it is of any help: http://www.samknows.com/broadband/exchange/SDMDDLT
NB. I have also put it through the master socket, changed microfilters etc and everything suggested but to no avail. It's difficult to know what to do because it seems to cut out randomly when ever a high demand is put through it...
A support ticket was raised back when it first started happening (on 19th Aug), but we never received a response (just a message saying, "There's been a problem with our automated troubleshooting process. Don't worry, our Faults Team will investigate it and be in touch. We'll aim to contact you within 24 hours. [INTERNAL]Failure of Circuit Check") Another ticket was raised on 26th Aug but was told it was because of our recent ADSL2 move and to contact yourselves again if it didn't sort itself out with 72 hours. It seemed to improve so we left it alone, but unfortunately it keeps coming back! Additionally, I then moved away to Univeristy on 1st Sept, and have only just returned, hence me reporting this now on behalf of my not-so-tech savvy mother!
Any help would be massively appreciated please!

[#2]

Hi there,
That previous ticket is showing as closed by the customer on the 20th August - not sure if that was yourself or your mother but that's why the investigation didn't go much further. Best bet is to run back through the faults troubleshooter and raise a new ticket to us.
Regarding the router, given what you've said it is possible that that could be causing the issue though I can understand your reluctance to get a new one. I realise it's a pain but you can test the router by using it on a different broadband enabled line (just change the connection login details as appropriate) and if it works fine there under load then you've confirmed it's not causing the problem.
If you could raise a new fault to us we'll get it investigated for you as soon as we can.

[#3]

Hello,
Thank you for your reply, and sorry for my late response!
I have managed to source another router and this seems to be working fine at the moment. Many thanks for your help!