I've a D2 auto and today I got a new front propshaft, my question is does it need lined up or is it just a matter of off with the old and on with the new?

Some say they need lining up... But i've taken a few off and never bothered lining them up and never had any issues

If it's a whole front prop it's all balanced and ready to go. Did mine a while back, quite easy. (I was just off my crutches after a knee op!) I did align the new with the same "orientation" as the old just in case in mattered, but I don't think anything technical needs doing, just replace one for one as it is. Make sure it's greased up, presuming its got nipples!

RAVE Procedure

The time to worry is if the sliding joint comes apart.
As already said, if it's a new prop shaft then it should be just a case of a straight swap. If it's the old prop shaft pulled off to replace the U/Js then everything should be marked up so that they go back in the same orientation.
Grease the prop shaft before you re-fit it, you'll find it easier and also consider fitting a longer grease nipple to the front U/J it will help you when greasing up in the future.

FYI - the nuts and bolts are 9/16 AF, not metric sizes. There is a long "socket" adapter available which makes getting at the bolts a bit easier too.