to find out what type of lintol that is above the plaster board, use a worn out drill bit,of smaller dia than the existing fixing hole, and drill up slowly and carefully into the hole and into/up against what the lintol is.... if concrete dust covers the worn drill bit, then you need to use a drill with the correct size masonary bit in to lengthen the fixing holes, if the bit is covered/has metal filings stuck to it, then a high speed steel bit is needed to extend the holes....
most new build do seem to stick plaster board to lintols....