PN
I suspect we are very nearly there and in a similar way to the Australian Defence Force (ADF) we will see the UK's Joint Forces Command (JFC) and PJHQ take a more leading role over the single services - just like the ADF or the Canadian Armed Forces (CAF). There are other similar models outside of the Commonwealth.
However, I am deeply opposed to 'single gateways' as they really are flawed on so many levels. Each Service has an ethos it needs to develop and nuture - those differences makes us who we are and more effective in our lead environments. Also, the idiotic notions of training officers, NCOs and Other Ranks on the same establsihments have been proven to be a bad idea many times over. As ever, we ignore the lessons of others at our peril.
LJ