I’ve been wanting to upgrade my 5610 to one of the screw back models, ideally a GW-5000u. My son keeps borrowing my 5610 so happy for him to have it if I can get something to replace it. I understand that there are 2 versions of the 5000u, the 1jf and 1er. They don’t appear on the Casio UK website and don’t seem available on Creation Watches. Understand there are fakes around so would appreciate recommendations for online retailers from where I could source one. Thanks