I'm sorry, but those results/app data is useless.
If you read through the details, the information it's recorded seems wrong.
Example, if you look at the data it recorded on the 8th March 2012. It's some how recorded 2 different speedtests, one connected through wifi, and the other connected through mobile broadband. but apparently according to your results, the mobile broadband and the home wifi had exactly the same external IP Address.
Another example, if you check your location, some tests are done from cherrycroft, and some tests are done when your by the motorway/bypass.
So based on the incorrect data from your mobilephone app, and the router stats.
The absolute maximum download speed you'l get is 3Mb, only if your line and home network setup is at optimum levels which it isnt on wifi. But according to the data, it's saying either the router is being repeatedly turned on and off, or it's losing connection.
Need to establish if someone is turning the router on and off multiple times a day, or is the connection dropping. If it's dropping then the exchange is turning the SNR up to try and stop it from dropping the connection, which is detuning your speed.