Welcome Andy from another Andy in Lincolnshire. You will love the bike when you get a few miles under the belt on it, nothing else has the presence of the Rocket !
Bull, in the UK we have a spilt licensing year, the 1st half (march-august) depicts the year then 2nd half (sept-feb) is that year plus 50...... I.e. Jan 2014 = 14 plate. Sep 2014 = 64 plate
So Andy's 57 plate bike was registered in the second half of 2007
I'm certain whoever dreamt up the scheme they was pissed up at the time because half of the UK still don't understand it and we have been using it 13 yrs now !