We have a 194/6 with an oil tank that makes a dreadful noise when either cold or hot and I wondered if this was a generic problem or maybe a poor quality tank.

They shouldn't make dreadful noises. Something is wrong.

The two I have owned with stock tanks made no noises

Is it being pressurizing by piston blow-by?

Let's see a pic of how it's vented.
Also what brand is it? Factory, vellios, patrick, DWD?

Is it a boiling noise? if it is the return tube, that loops to the top inside the tank may have somehow broke off.
The return scavenge oil has a fair bit air in it, the return tube loops to the top where the oil drops through a screen designed to separate the air from the oil.

You will hear gurgling noise at times, so define " dreadful " noise.

I've never heard of a factory tank having items in it come apart in the tank - but then, I don't operate a shop.

First time i started up my 3.6L i had accidentally left the vent plugged.

The results could certainly be described as "dreadful noise".

Mine gurgles when it first starts up.I have a 930 oil pump so it scavenges from the case at a higher volume.

The 911 guys say the wrong type of filter can do this,don't know from personal experience however.

did it just start? what did you do? ... mine make none that i can hear

My two previous Sixes (original) never made a peep from the oil tank. My current one, the two times I heard the engine start, run and drive, never said a word either.