Kitchen extractor fan in listed building; worth the agro ? ?

Current kitchen in leasehold flat does not have an extractor over hob. About to replace units.

Is it worth;

1)the agro of getting listed building consent and
2)freeholder's consent

for the extractor to go through the ceiling into attic, to be vented in the roof valley and

3)the expense of getting it done

Or shall I not bother

I'm in two minds.