G-suits did exist by the end of the war. Commander Crosley's book "They gave me a Sea Fire" describes the use of a water filled G-suits by the British Pacific Fleet after 1944. If the RN was using them the suits should have been avaliable to the RAF, USN, USAAF etc.
Gill's uncle was given a water-filled one to trial in his Spitfire.
It kept leaking and led to lots of mickey taking from his mates;
"wet yourself when you saw the enemy did you Steve"?!
I talked to a Sea Fury pilot at Yeovilton, he had pulled 12g coming
off a target in Korea - it rippled the wings!
(The g-meter was for the maintainers and located in the wheel well).
lsh