I remember a fitting donkey years ago that was a retro fit for an internal overflow.
Involved drilling a 3/4" hole into the side of the siphon.
Fitting had a small float and an elastic band :ohmy: absolute nightmare to set up.
My water bill went from £450 a year to £1300 after the meter was fitted:eek: They kept sending me letters that they were concerned ffs! I told the three wimmin in the house to cut DOWN! They said I didn't have any hair and they wouldn't cut down as they all had flowing locks that needed to be...