Hiya,
Welcome to cableforum!
Err - I'd save yourself the bother and pay the £50 to get an installer* out to do it. Although it is possible there are a lot of problems that can crop up... and if you have any problems after it and someone has to come out to fix it you will be charged the £50 anyway...
*I've been told off by an engineer friend of mine not to call them engineers
