when in 3rd gear if u go to chnage out of it its really efing hard but if u push back up towards 3rd it comes out fine as u change out, same deal with 4th, when it sticks if u pull down towards 4th as u push up out of the gear it comes out fine, does anyone know what is occuring here?

How many K's you got on it???...what model are we talking about here???
Have you changed the g'box oil???....if so, did you replace it with the right oil???
If cable clutch...may need adjusting or replacing ( clutch)....if Hydraulic, then change fluid....if no change, then clutch may need replacing.

it's an 02 ba xr6 ute, bought it on 95000 its now on 105000, when I first bought it this problem occurred fairly regularly but it only happens once in a blue moon now, I have not replaced the gear oil or done anything to try to fix the problem, could it be the synchromesh?

cheers

Change the oil in the g'box.....see how that goes.