Oil in Combustion Chamber is HG or Valve seals. or rare its piston rings
Coolant in Cylinder can only be ?
inlet gasket as you said or the Dreaded Hg ..
Unfortunately just because a garage did it . doesn't mean its been done right
, more often than not they do it wrong ?
Ours had failed about 20k down the line from a garage repair and found they had put in the wrong gasket for the liner heights on our car .
C