MikeT wrote:

With it all thrashing about all I have done is make a big mess on
the brick surface with the core cutter tips. There were no
instructions with it but I would have remover the pilot if I ever
got far enough into the brick to do so.

The only thing I can think to do now to recover the job is to
either buy a 13 x 250mm taper drill and use that to get a good
clean pilot hole to guide the core in, or grind down an sds
shanked 13mm drill I have here to fit the arbor and use that as
above. 3rd alternative would be a bit of 10mm silver steel rod
and grind a taper on that to fit the arbor to get the core
started clean.

Maybe bang a piece of scrap metal tubing into the pilot hole to make a
discardable liner?