In article
Tim wrote:
The wall intro which I want to fix a pair of brackets which will need
to support a pair of 18 litre water cisterns is about 200 years old
and appears to be a mix of mortar, stones and rough looking brick. I
guess is is a typical wall construction for the period. It is a
georgian style city building.

Can anybody suggest what fastening method I should use; rawlplugs and
body filler, rawlbolts etc .. ?

I'd fix something floor-to-ceiling to take the weight - fixing into the
masonry will probably fail and take a chunk of wall with it. Or maybe
you can fix a few studs through the wall with a steel plate on the other
side to spread the load.