Hi there Hill Spud, and welcome!
I've checked your area, and it seems that the problem here is congestion, sadly. When a cell site becomes overloaded - no matter the signal, this will affect your download speeds. In the meanwhile, there may be times of day that you find better or worse speed depending on traffic - if this is the case, it confirms what I can see.
There is some great news, however - we've spotted this and are setting up a new 3G site just by the Pelham Hotel - not too far from you! I have no timescale for this at the moment, but most of the details are up on our system, so I have faith it won't be too long!
Other than this, you can improve speeds by using an extension cable (to lengthen the distance the modem stays from the computer main chassis, and it's electrical field), as well as perhaps positioning the computer closer to a window or even another room.
Let us know how you get on, and if you need anything else!
Daz
eForum Team