Do what I did. The internal wiring in my house was dreadful, which is not unusual.

By a cheap DECT cordless phone with enough extensions to go round the house (I got a 3 handset model for £12 delivered off ebay).

Take the cover off your NTE5 master socket and disconnect the internal wiring from the faceplate. Put the cover back on. Plug in a microfilter into the master socket. Plug the Vigor and the DECT base station into that.

My sync speed went up from 4-5Mbs to 7.3Mbs with this simple fix.

Note that this made a much bigger improvement than putting in a faceplate splitter by itself. The house wiring was still having an effect on the line to the router.

You can "try before you buy" by disconnecting the faceplate and plugging the Vigor directly into the master socket to see if it makes much improvement.

Broadband Self Help

So what can we do ourselves? There are no promises but I have had great results.
Typically in the villages many of us should be able to get 2Meg download speeds, so what stops us? Why are many of us only getting 0.512Meg (512k)?
There are many reasons some related to the BT infrastructure outside our control (distance from the exchanges either Worcester City or Fernhill Heath etc).
There are some thing that we can do especially if we have our own internal extension wiring in the house from the master BT incoming socket and if we have our broadband routers plugged into the end of these extensions (for example in the spare room office).
I assume here that the actual extension wires themselves are in good condition and of the recommend specification with good connections.

Recently BT announced the release of the iPlate a little device that sits between the back part of the BT master socket (BT access only) and the front part where we connect any extension wiring (some homes may have different arrangements).
Our telephone wiring goes back some years and has an old bell wire to ring the old style telephone, not much used any longer. This bell wire does not help the high speed broadband signal as it is extended around your home, the iPlate filters/ disconnects it at the master socket and this reduces the noise pick up that slows down your broadband connection speed. I applied the bell wire disconnect and my speed went from 512K to 1.6 Meg. The iPlate also has what is called a common mode filter which goes further to reduce the noise on the telephone extension cables and the addition of this raised my broadband speed finally to 2.1Meg.
The iPlate does both of the modifications in a flash although it may take a few days for the exchange to work up to the higher speed that is now possible as it amends the statistics for your improved connection.
If you are a BT broadband customer you can get the iPlate for about £1.20, if not it costs about £8.00 (cheeky especially if you pay them telephone line rental as you are paying for them to fix a legacy system issue in solving the bell wire problem).

The web addresses here explain the detail of the iPlate fix and it is as simple as removing two screws inserting the module (plug it in), reconnect the screws. Then if you are lucky in a few days you can go and enjoy your favourite sites like BBC iPlayer with less interruption.
http://www.btplc.com/News/Articles/Showarticle.cfm?ArticleID=8a439fe9-b694-47f5-ba64-c73ae2395366
http://www.broadbandbuyer.co.uk/Shop/ShopDetail.asp?ProductID=7256
http://www.thinkbroadband.com/faq/sections/install.html#226

If you decide to try this please follow the installation instructions provided by the iPlate provider.
Good surfing!

I just disconnected the bell wire .. my rate shot up.

Me too Dan. I got an extra 1Mb. 8)

ADSL+2 Soon.

There's a diagram of how to remove the bell wire here:

http://www.draytek.co.uk/support/kb_vigor_linefaults.html