Okay, so for anybody who us interested in getting a Google Music account, there are two guides available.
This is the main one that gives the instructions quite simply and another which gives more precise instruction on configuring the Tor Browser tool.
Main guide -
How to get access to Google Music from the UK | Red Gamer
Tor Browser configuration guide (where it talks about configuring the US node) -
How-to: use Google Music from anywhere (yes, outside of the United States) -- Engadget
Essentially what you need to do is this.
Create a new Google account by masking your IP address as being from outside the USA. This is done by using the Tor Browser tool which contains a Firefox within it. Choose a US node from the Tor network map and configure the browser to only use that node. This is the only tricky bit but follow the guide and it's not too difficult.
Once you have created a new Google account with it thinking you are in the US, go to the Google Music site and register for it, linking your new Google US account to Music. Still by being connected to the US Node.
Once that's done, that is it. Download and install the Google Music apk onto your phone.
Add your new US Google account onto your phone, start up the new Google Music app and it should ask you to choose which Google Account to use Music with (ie. the USA one).
Download the Music Manager program onto your home laptop and load music onto your Music account using normal internet connection.
You only ever need to use Tor Browser again if you want to buy music off the Android Market, which isn't that cheap from the UK anyway.
Useful guide?