Oh, that one is interesting.
Buildings are mapped separately, following UrbisAdm.

It looks like Unilever House is the whole block except for this one: https://www.openstreetmap.org/way/260209647 which is more recent.  We could possibly draw a (multi)polygon for Unilever House, with the appropriate heritage tags but no building tag.

This one seems to have to be included too but it already has a name.
https://www.openstreetmap.org/way/260209657

Any idea how we could solve this?  What do you think?