I agree that ca won't stop a split, if it's gonna happen there ain't no stopping it.
I also don't like the idea of filling it. Strip it off and do it again with some real wood init?
Elm, Laburnum, Yew, Olive and all the Burrs thereof, we have some fantastic native woods without sodding about.
Before Neil spouts off about not being indigenous, I mean home grown. 
