
Due or able to leave for their new homes? There'd be a 2 month difference.
Why not go to the Breeders section here and see what comes up. It never hurts to get on a waiting list which you may have to do. Also look at a relevant Breed Club website as this shouild mean you avoid BYBs.
Page one of the Golden puppy list here shows a litter due around mid March - in Glos. Another due in June, Lancs. And that's from one page.