i have head after so many k's that you are supost to turn head bolt 1/4 turn
true or false
Do you used the original vw stretch bolts ? then yes after 1000 km/621 miles according to the manual
I'v read here they do it after the engine had been at operating temp
true or false
Depends.

What engine? What headgasket type (fibre or metal)?
its a 1.6TD with a metal head gasket
Re-torquing is not required with a metal headgasket.
I still re-torqued mine even with a metal head gasket- I thought re-torquing was a function of stretch bolts and not gasket material? The Bentley said 1/4 turn after initial warm-up, and another 1/4 after 1000 miles. The last 1/4 turn was really, really hard.
Brendan