Good point Bill, it looks like a very porous weld too. If a welded repair is done again, I would use a sheet of glass and grinding paste to make sure the mating surface is true. Ally brazing rods will fill in all those holes and with a bit of work and a buffing mop, it could look like new.
NB: When I say 'All those holes' I was referring to the porous marks, not the blo*%ly great big one where the primary chain escaped!
