No just weld the straight part of the tine on. With the tine layed flat covering the allen key hole a few tacks either side should be enough to hold it then leave to cool. The tine will then act like a spanner and a quick tap with the hammer on the end should undo them. Old grub screws or worn down/rounded off bolt heads aren't too easy to undo but this trick works very well I've found.
Ok ta, I'll give it a go.