*Whether women will ever command a combat unit remains to be seen and will be a whole merit based decision."
I think this is a very important point, and sadly I think it's going to come down to more than merit, it's going to come down to stability of the world and a pinch of luck.
Let's look at the commissioned rank structure.
So 2019 woman passes Sandhurst and joins infantry regiment. She is now a 2nd Lt, after 1 year as per commissioned rank structure becomes Lt, holds this position for 2 years on average. Next jump is Captain, that's plausible so now after let's say in the space of 3-4 years she's manage to get to Captain (yeah sure). Which is bloody amazing if she could but as you say selection for moving up rank is based on merit and experience, so how likely is she to get to Major?
Many infantry units have not been "used in a combat operational role" for many a year. So you probably have some Afghan experienced officers still knocking about who will always jump ahead of her.
So she would need operational experience, well now we need to deploy mass infantry regiments to war. Which I don't think is likely to happen any day soon, after the Iraq inquest the withdrawal from Afghanistan I don't think any government is jumping to deploy boots on the ground. Especially when they can all play a game of cloaks and daggers with SF ops teams and drones.
I think in the army everyone seems to have stalled when it comes to being made up, and this goes for NCO and CO, and it's mainly because of the experience needed to qualify, people are simply not getting the experiences. So is the answer change the qualification criteria for progression? Possibly?
Sign off and retention rates are absolutely shocking, so perhaps they are hoping for a small surge of recruitment from this but sign off rates after year 4 and 7-11 for officers I think will still remain high.
There is no good pension now, no retention bonuses, no deployment bonuses in most regiments. Rumours of slashing LSA is rife.
Sorry I've digressed massively there anyway in short, I don't see any woman in a combat role getting to a high rank any time soon sadly due to lack of opportunity (but then again the lack of opportunity is no wars, which is good globally) it's a mess.