Thanks pal.Bonding is recommended for concrete but if you are unsure try one of the premixed bonding agents like gyp bond or blue grit Etc.
Hard to say defo without seeing it but carlite bonding sticks to most things and is the plaster BG recomend for shuttered concrete .Just make sure there is no more water ingress .Thanks pal.
This was up before blue grit, maybes 2001 or something, the place was built. To be fair, I've had some difficulty getting it off, it's stuck but good to the wall.
You reckon just bond it out and skim over as normal, then? I don't have to do anything special?