had a look down there, couldnt see much, pulled the barrels up a bit, still couldnt see anything, took barrels off and it appears the timing chain has doubled over itself. At the point where its longest, theres just two links doubled over themselves, but are caught underneath the crankshaft! I'll keep pulling and rocking the crankshaft, but if it comes to it, does anyone know if I can get decent access to it if i remove the sump?