Hi, need to replace a failed boiler expansion vessel* how critical is it
to place an additional (replacement) expansion vessel close to the boiler?
From what I read it seems the concensus is as close to the boiler as
possible or Bad Things will happen, but I've also seen installations
where a system boiler has an expansion vessel in a remote cupboard. So
it can't be all that bad?

*Vaillant, so no surprise there, but it did manage to last a few years.
I really don't want to demount the boiler to replace the internal one
and space around the boiler is very limited, hence the question.