Can anyone tell me what these are please - I need to order an overflow
/ waste for a bath in the very near future, and i'm not sure whether
one of the pop-up "turn the knob" or clic-clac might be more suitable
/ sensible (it's a whirlpool jobbie).

I suspect they're a captive plug, which you push to engage or
disengage ?!?

While i'm on the subject, the taps have a central mounting position on
this bath, but I don't know if they'd be better on the "exposed" side,
or hard up against the wall (aka impossible to get to if you have a
problem) - any pearls of wisdom please ?

TIA ! :-)