Cole & Mason Salt and Pepper mills button

Recently, a friend asked if I could help with repairing a set of Salt and Pepper mills (Grinders). The items were made by "Cole and Mason," and were decent quality but the push button on the top of each mill left a bit to be desired, design wise. The button originally made from what appeared to be some kind of thermosetting resin (Bakelite like stuff) and appeared to have originally been retained by small tongues off the button body. Needless to say, these eventually snapped off, and the spring loaded button popped out.
So I set about designing a suitable replacement. I gave up trying to print the tiny little tangs as I knew they wouldn't last long. My design uses a pair of countersunk screws, 1 M3 x 8mm and an M4 x 10mm. The printed button is fitted as per the original but the two screws fit into the button from inside the pepper mill top case and secure it in place. The M4 screw also acts as the plunger to operate the switch on the mill motor assembly.