I'm not in the military but I am fully informed on it as I have a military background and I am a journalist (but nothing posted here would ever be touched).
My advice; get a few of you together and approach a Sunday redtop, they love campaigns and this would be a very topical one as it was splashed all over the daily redtops.
The Times or Sunday Times would be a good bet too, although the Telegraph may be a bit too rooted in the system to be of a mind to go against their readership.
If the papers see there's a group of ex or current military bods very angry about the treatment of war widows they'd be on the case in a flash. The reason they're not already is because they don't know the daily reality of service rules but when informed they'll be gleefully sticking it to the MOD and His Hooness.
I wish you every support in your campaign, if you decide to press on, as I had many friends who were ex-RAF of WWII vintage and spoke of such archaic rules with resignation with regard to lost colleagues.