My "James Dalafrom" toilet has central flush with button in the middle of the toilet tank lid, the toilet continually fills and drains I need to purchase replacement part number 17.30.21 - 1 or 20.03.23 - 3, both of these numbers are on the part.
I am having the exact same problem as you. My wife however says the commode was a Kohler. I have contacted Kohler factory and they say it should have a K-XXXX number which I say doesn't appear anywhere on my commode. Please let me know if you have any luck.