Question about species lists

Taxonomic question, tangentially related to iSpot - would you regard the NBN Atlas or the NHM as being more definitive and/or up-to-date?
I’m looking at a minor order of insects and there is a significant difference between the two websites in their interpretation of what is and isn’t a good species. My sense is that the taxonomy on the NHM site is the more current, but I don’t really have a larger frame of reference within which to form a judgement.
It’s possible of course that the position may vary by taxon.

As far as I recall the method is that the scheme or soc associated with that group forms a list then passes it to NHM who compile them all togehter then pass on to NBN. However there may be various modifications to the method e.g. it may not be scheme or soc for that group who makes the list for the group (there may be no appropriate scheme). It is also possible that certain groups go directly to NBN and there may also be some coordination with GBIF.