Don't know whether there is any one place you could contact. You could try the Ministry of Defence directly through formal channels, although the establishment prefer to hide the casualties of war, and might not be very helpful.
For older veterans: WW2, Palestine, Korea, Malaysia , Cyprus, Suez, Northern Ireland, Falklands, Gulf 1 and 2, plus numerous post 1945 colonial insurgencies you could contact the Royal British Legion, who through their branch network, will have members from all those conflicts. There is SSAFA( Soldiers, Sailors, AirForce Association) which is the welfare organisation for all branches of the forces. There are also the RAF Benevolent Fund, Royal Navy Benevolent Fund and the Army Benevolent Fund.
Contacting Simon Weston at Simon Weston.com might be useful. He was seriously burnt in the Falklands War, and has been extremely active ever since campaigning on ex servicemans issues.
If you want more recent cases Gulf 1, 2 and Afghanistan, you could stick something on the informal blog of the British Army: ARSSE at
www.arsse.co.uk.
There are also dedicated PTSD organisations such as
www.ptsdresolution.orgHope this helps