The best way to fix conduit to the wall is to use plasterboard nails either side of the conduit.
If you have trouble knocking the nails in, drill 5.5mm holes in the brickwork, insert red plugs, and knock the nail into that.
If you have trouble knocking the nails in, drill 5.5mm holes in the brickwork, insert red plugs, and knock the nail into that.