Np5 will be twin seat Mk1 catering to imporvements gained from Np1/2. 3 and 4 will be Mk2 prototype.
https://web.archive.org/web/20150214013624/https://www.livefistdefence.com/2015/02/part-3-official-lca-navy-mk2-wishlist.html
I have the full video on my drive- the youtube ver. is a cut short...