I think injected polyurethane foam insulation (non breathable) is a last resort for homes with non standard width cavity walls where the brickwork was crumbling and in such poor state (with failing wall ties etc) that literally gluing it all in place might not be a bad thing. It is not promoted as a solid wall insulation option. You’ll know if you’ve got solid walls by looking at the pattern of the brick laying. If there are short brick ends intermixed with long brick lengths it’s a solid wall.