Well, I had a rummage in dad's garage again, and this time found an arrester hook form an F6 that was scrapped at Cranfield in the late 90's. It's still attached to part of the leaf spring, which had snapped in two over the years of standing outside in all weathers.
So I took a few photos with a tape measure in shot.
Hope it helps with improving the Lightning model accuracy. Please feel free to use the images as skins - but do note that there is a certain amount of splatter of grey paint on it from when the aircraft was last painted by the RAF!
The main body material is stainless steel, with a spring steel leaf spring, and a steel wedge.
Note the abrasions from use, the tarmac scuffing on the wedge, and also abrasions from the arrester wire on the main body. Note the rust marks in the "U" shaped groove left from the steel arrester wire (as stainless doesn't rust!)
The wedge is normally held in the stowed position (as per the above image) by a rubber block on the airframe pushing against the lever at the rear. It flops down to help catch the wire.