could be coming from small hoses on oil cooler mine were pin hole leaking
these hoses are cheap 4 or 5 bucks each, but a real PIA to get off /
install. Also the pipe from water pump to thermostat housing was leaking
another pin hole leak. had to remove that to have it sand blasted and
welded up. I'm lucky I took it to work and asked a weld on Rolls-Royce
aircraft engine parts if he could weld it up...he said sure...
I freaked out when I got it back!!  it was unbelievable. twice strong as
stock, and nice work. So nice I'm looking for a spare to have him do it
too...It's better than NEW.

another place to look is on thermosat housing where it bolts to
block  O-rings tend to leak, ditto that small plastic on under alternator
with 7mm hose when alternator belt breaks these break too.  older ones are
metal, later ones are cheap plastic.  also VW sells both O-ring or gasket
for this part.  parts manual isn't really clear on that. I prefer O-ring.

also check condition of all you hoses. mine were good shape but with
107,000 I elected to replace them all / save old ones for emergency spares.
replacing all those hoses wasn't cheap... 400 bucks.

I'd check all these out before assuming its head leak...

mike