Resin anchors (1M8) have been specified (by the structural engineer)
for a slapping I'm doing. There's a steel standard (PFC) to go up one
edge of the slap which has to be fixed to the end of the wall. It's a
single brick wall so I guess that's why resin is used, expansion
fittings might be a bad idea.

It would be good to have the PFC in place then drill and place the
fastenings. Is this possible, what's the relationship between the
diameter of the resin capsule/hole in the masonry and the diameter of
the stud/hole in the PFC? It looks like M8 resin capsule are 10mm
diameter.

Are there different types of resin? I've seen capsules advertised as
for concrete and natural stone. What about brick, do I need a differnt
resin? I'll be using solid or frogged brick rather than ones with
internal holes.

Extra credit question. Some fixings are 1Mx (e.g 1M8 resin anchor) and
some are 2Mx (e.g. 2M12 and 2M16 rawlbolts). What's the significance of
the numerical prefix?