Okay good luck, I hope it all works out well for you in the end.

So they are saying that you could make the direct swap and block off the original vent hose with no consequence.

How does the excess coolant vapour pressure get relieved then? Is the Coolant Expansion Tank Cap equiped with a pressure relief device? I can see how that could be a reasonable substitute for the vent hose function, if indeed it is.

If not, does it mean that in an elevated engine temperature operating condition and/or engine overheat situation, the only solution would be for the weakest part in the cooling circuit to burst? This would be highly undesirable/ unpredictable and could be costly except if there is a known intentional weak link designed into the system by BMW.

Please do well to clarify the above with them. Inquire to know what were modified, if any, when the vent hose was "deleted"