Thanks Pulaski. My thinking was if something should happen to me, my wife would get it, access to my 401K but the British Military Pension would be lost to her?
So there's no widow's pension? If not, then it might arguably make sense to "cash out" your pension, but depending on your circumstances there might be other strategies such as using part of your pension, especially if it is generous or more than you need for living expenses, to pay for life insurance which would pay a lump sum in the event of your death and loss of pension. In the event of your wife predeceasing you, you'd still have your pension and could drop the life insurance.
Before you take the precipitate move of cashing out your military pension you really should get some professional advice and explore the implications of what you are proposing and what viable alternatives there are.