What is "GH"?
General Handling - probably started of as an RAF Central Flying School term as it is still used today.
Basically it described any kind of flight which doesn't fall into other categories*, such as circuits, stalling, "general" flying exercise (steep turns etc). In the military sense it also includes aerobatics (if pilot and aircraft are cleared for such use!)
*such as IF, Nav, Formation, etc...
An example:
If at work I was asked to demostrate a "GH package", the flight would probably run along the lines of this...
Take off
Climb to height
Spinning
Stalls (academic clean, finals turn stall, final approach stall)
Steep/Max rate turns
Aerobatics
Circuits (all the variations; Normal, Flapless, Low level, Glide)
Also a PFL to a field would appear somewhere during the trip too.