Only the original Seiko battery, with its protective film, has tabs to help installation and cuts to allow electrical contact. Since Seiko batteries are difficult to find (Cousins UK has them, but do not ship bt post internationally) and more expensive, Panasonic (the only other manuf.) is normally used, and do work perfectly, as my daily beater witnesses.
Actually one can see a small round notch at 9h, there must be a reason for that?
And assuming it's a front loader, then the crystal must be removed using a lifter (do you have one?) something that may leave some marks on the sides, can you see if there is any? The alternative could be a syringe.