Looked at a job earlier,the render has blown and has to be hacked off.the wall is part of a knock through extension so there is the original lathe n plaster section then a brickwork chimney section(flush with the rest of the wall)then it goes back to lathe work the other side then the extended part is studwork.just gotta hack off the wall upto the plasterboard section but not sure of the best option for the re render work.bonding with mesh in or s&c with a scratch with fibres then topcoat.then I will reskim the whole wall again to finish.