Thanks Guys, interesting idea's. Can't use the carbon fibre as this is a BAE Hawk, the tail plane is canted downwards as per the photo.

I would have thought that the plywood bearers are strong enough as there is very little movement when I try to twist the two halves. Obviously they need finishing of and then glass cloth added to strengthen everything.

The wood supplied for the root is awful, hence not going ahead with it, I just fitted it to see how it all worked.

On the made up tail plane, the 25% MAC line is shown in red and the original pivot positions are shown in green and the bolts go through the washers. After all the discussion, I was going to make the tail plane pivot close to the aft bearer as that is very near to the 25% MAC line. Some extra bracing would strengthen things up as well.