My advice is to put as much distance between you and your "partner" as possible. It will be a distraction that you don't need. Your primary objective should be receiving HM's Commission at the end of your training. It's seldom wise to split (no pun intended) objectives. With the best will in the world, the temptation will be thrust upon you.
In answer to the question: It makes sense to wait until you know where you will be based before making hard and fast plans. After training, the steep learning curve will continue in your first appointment and if it is a ship, bear in mind your partner will be spending a fair bit of time alone whilst you are at sea, away from the baseport area - you could be away for six months. If eligible, Service Family Accommodation is available in the baseport area, usually within 6 weeks of being appointed to that area. Private rented accommodation is obviously available from as soon as you arrive there.
Guzzler. Sorry, at 0043A I wasn't feeling very eloquent.
Being Commissioned is the beginning of further training for life (not a job) in a blue suit. Ninja_Stoker has since explained my underlying point very well.
The "partner" was not a dig at GrapeVine but a recognition of a modern day manifestation of political correctness that takes all precision away from true representation. Are we talking long term girlfriend, fiance, wife? I don't know and it could just as easily be a bloke in these enlightened modern times.
alfred_the_great. That's good to know and congratulations on a successful outcome. There is always the possibility that you weren't just your average bloke with your average, then, girlfriend, though. As I said, it was my view, for what it's worth.