I have set up regions - associated to regions are events - associated to events are species (drawn from an event_species taxonomy)
For clarity
Region - Japan
Event - Winter Wildlife Photography Holiday in Japan
Species - Blakiston's Fish Owl, Red-crowned Crane, Snow Monkey, Steller's Sea Eagle, White-tailed Sea Eagle, Whooper Swan
on the region summary page I display a list of the events - each of these is listing the species - this is working fine
In the text at the top, I would like to insert a distinct list of all the species of the associated events - how do I obtain such a list?
I attach a screenshot of the Alaskan page - this is a great example as the summer events and the winter event have some of the same species, but some different - I would want the list to contain the species from all events, but in a distinct fashion - in the attached page, I would insert the distinct list in the sentence which reads 'to undertake photography of various species that are available within the region' - so it became 'to undertake photography of various species that are available within the region, including [list of linked species here] & more.'
... is correct - so I have a view for displaying the archive of a taxonomy - region - which displays the posts - events - belonging to that term - which in turn have associated taxonomies - species - it is the species for all associated posts that I want ... in a distinct list
It's not clear from what you wrote whether you have a custom archive made with Views for the region taxonomy archive, or whether you have created a View which does the same and is added to a page. (What you should avoid is creating a custom archive and adding a View to it instead of the archive output.)
In any case, what you want requires writing custom code, which will depend somewhat on whether this is an archive or a page with a View.
It will need to essentially replicate the archive or View query to get the same set of event posts, and the loop over them, getting the assigned species terms for each post in the loop and building up an array of terms once you have tested they are not duplicates and then using that to generate the result as a string.
If you try and tackle that and run into problems then let me know. It is outside our support policy to provide such code, though we try and help as much as possible, time permitting, so do ask if you have specific questions.