Plenty of doumentation available Riders hand book,richardsons etc all available to purchase on line
all needing interpretation materials oils and riders abilities have altered in 70 years
http://www.amazon.co.uk/Vincent-Motorcycles-Paul-Richardson/dp/0952066238 (not that I should reccomend those people after seeing how they treat their staff)
flea bay, Vincent spares companies
and of course vincent owners ..... JOIN THE CLUB
personally I bought all the books and read them before I bought the bike and that was when bikes cost less than £100
NB The thought just struck me, you mean you bought a Mossy Vincent second hand and at that price the old owner lost the instructions.....