Bath overflow hole size confusion ? Pop-up waste

[garyharrison]

I am trying to fit a new 'Pop-up waste' to a bath. I remember the original 'pop-up waste was difficult to fit because the washer wouldn't sit right and it leaked. It seems that the washer/ seals supplied with the new waste are designed for a 50mm hole but the baths waste hole is only 45mm. What size is the overflow hole on most baths ? Are there different sizes ? Do I have to find a Pop-up waste to fit my 45mm overflow hole?
Thanks in advance.
Gary

 

[shedman7]

Bump.

Have exactly the same issue - bath overflow is 45mm but the pop up waste to attach is for a 60mm hole.

Suppliers don't seem to specify size, so what do people do?

Drilling out a larger hole doesn't seem ideal, could I find a 45mm fitting anywhere or make the current overflow bigger to fit?!