Yes I have Dave , used a 6mm carbon rod stuffed it with glue and rammed it into the 8mm Cf rod now nice and strong..hold down really well wont be moving off there,in saying that the elevators should have also been glued for strength as they pretty much do as much control as the vertical fin but they not glued either ..ive seen Airline vertical stabs held in place with pins and bolts too seem pretty ok so far hehe! the screws go all the way through and into the other side wall as well as its underneath the 4mm top plate so the bolts are in sheer I think the only way you are going to remove this fin is to remove all of the airframe in front of it
cheers
H