Forces Pensions are administered under clear rules and there is a whole host of resources here for you to draw upon.
http://www.mod.uk/DefenceInternet/AboutDefence /WhatWeDo/Personnel/Pensions/ArmedForcesPensio ns/AFPS75/
There are two basic schemes AFPS75 and AFPS05. The latter applied to those joining after April 2005 - I assume you were in the earlier scheme.
This link gives you access to the AFPS75 scheme booklet that you can also read from here: -
http://www.mod.uk/NR/rdonlyres/73C97FDF-BCDA-4 B3F-A686-CA8533FD52BC/0/afps75_mmp106_your_pen sion_scheme_explained.pdf
From the booklet on page 11 under Invaliding Benefits it says:
If your career is cut short by illness or injury (which is not your fault) and you have completed more than 2 years reckonable service, you will receive an invaliding pension and a lump sum.
This would appear to be your situation - so one wonders what happened on your discharge - were you not given money then? If so, that's it I'm afraid. You do not then get more at age 60.