Depends on which type of plans your after and full set of builder plans for instance, if so for the Sunderland built vessel begin by contacting:http://www.sunderlandmaritimeheritage.org.uk/index.html
or search the web.
For the 2012 build try the owners/owner, CEO etc., and show them something you have already built and don't, under any circumstances, waste their time. However, the reality is that you have little or no chance of getting anything off them until you have proved yourself.
One of the joys of model building is the research aspect, I've given you some leads now pick them up and run with them.
Best of luck,