They wouldn't have the extent of stock of the Book Depository but Kenny's are good. It is an Irish company and they provide free delivery within Ireland. Easy to contact by phone with queries.
I use Kobo as an app as I hate Amazon.
https://www.kobo.com/ie/en/ebooks/ireland
Good selection and I downloaded the app to Desktop and Mobile so I have everything in one place. I moved away from books but will sometimes buy one.