Obviously you haven't had "decent nutritional support" if you've been "focusing on adding size" but still gone six months without seeing any size gains.
Again, you very clearly haven't been taking in enough. On the most basic level, there's a truth to: "Wanna get bigger, ain't getting bigger, need to eat more." You really should've asked this question after month two of no noticeable weight gain.
Focus on one thing at a time. Gaining size or getting lean or, actually, playing rugby at your best. If you're in-season and having games on a weekly basis, it's not really the best time to worry about body composition. That's something to be done, ideally, in the offseason.
So you're lifting four days a week, have two "conditioning"/rugby training days, and one game day. And based on your rest days, it looks like you're training twice a day at least a few times a week.
That's a lot of activity, so you shouldn't be scared of carbs (you're earning them through training) and you shouldn't be scared of fats (they're essential for growth and recovery, and your "standard day" is pretty low fat).
On a day like this, between which meals are you training (lifting and/or rugby)?
Do you have any specific workout shakes before, during, or after training? That alone can make a huge difference by adding several hundred quality calories on days you train.
Overall, it looks like you're on a low fat, moderate carb plan. That might be alright if you were looking to maintain, but you're not. You're training hard (presumably), so don't be scared to eat hard (to an extent, of course). This article should give you some ideas to come up with a better general plan: