YD - with the greatest respect, you may have heard 'numerous' academics suggesting this, but there are members of this board who have heard other, equally - or perhaps even more - distinguished academics offer a less clear-cut opinion on the relationship of the P5 seat to the retention of Trident (or a much more limited nuclear capability) when attending the Staff College on ACSC; or, when on ICSC will have heard other academics with a specialism in IR put forward a view contrary to the one you've expressed.
There are a fair proportion of Ppruners who've studied this at Masters level, so telling them what your professors have said isn't necessarily going to carry the day on this...