My builder installed insulation board over the existing solid brick walls in our new kitchen. I need to install anchors for string shelf supports but haven't had any luck finding the right ones.
I've drilled through the wall to the brickwork. Depth from inside face of wall to brick is 110mm approx. There is studwork attached to the brickwork and then either 12 or 18mm plywood attached to that. Then the insulation board and plasterboard on top. My problem is that there is only approx 45mm gap between the brick and plywood so the anchors I've tried to install (link below) can't rotate up to grab the plywood as they need just a bit more room than I have. I tried shaving off some of the brick with a long sds bit but don't have the space to manouever it and don't want to damage the outer wall with my fiddling.
This is an image of how the builder explained it is laid out, and it seems to fit with my drilling: 
Here are the anchors I've tried. Any suggestions?
Best Answer
The plywood is robust enough that I'd hang your shelves on that with wood screws. If they're very heavy, hit the plywood and the studs. You may get some bending of fasteners, though, due to the span to the face of the wallboard, so use fairly heavy screws (#10 or better).
I see no reason to anchor into the masonry. By the time your screws pull out of the plywood you'll have serious damage to the drywall anyway. That's unlikely unless you go nuts with the decorative plates and load your shelves to an absurd degree.