/admin/* pages "The website encountered an unexpected error"
Just to get this marked off as answered (with thanks to Clive).

First of all was understanding how to make use of the database watchdog table to find the errors. You have to download and view the variables column... the error's in there. In my case it was that cURL was not installed. 

It was as simple as installing cURL and restarting the Apache service. 

apt-get install php5-curl


Thanks again to Clive!