For me, the plate isn't important, neither is the £xxx.xx difference in depreciation over the next X years. The diesel on this beast is going to do you for far more than that, so just enjoy it I say! As someone else said, life's to short to worry about these things.
if you're frugal with money, and care about the odd few £100 here and there, then of course wait. Or if the '14' on your car is important, then by all means, wait. Otherwise, you're missing out on 'breaking in' time to allow you to fully enjoy the car come 2 months' time, at which time you can really enjoy it!