1960 house ... Mortar under plaster? 1" thick

[sean oc]

What should I use to fill in the knocked out wall?
Its about 1" think from brickwork and then skimmed over with plaster, is this a mortar mix of some sort?

I want to fill it and then get it skimmed? what should I use ?

Thanks Sean

 

[Chri5]

Render by the sounds of it.

Use bonding to bring the sub plastering surface level, then re skim.