Heh I was the pioneer batch of Sea Soldier - the physical trainings are not so tough, maybe more on running. Swimming training not so much (cause you won't get to use the pool much.)
It will be a stay in course for around 3 months. Then afterwhich you will be assigned into either sea side security (outpost, RHIBs) or land side security (vehicle checks, sentry duties). The duty system is one day duty one day off. Technically this sounds great but actually you only get to book out around noon the next day. It's live ops, so if your duty falls on a public holiday you have no choice.
If you need more information just PM me.