Doctors' line (sick line) - when do I return to work?

[dancerdog]

I have just looked at my sick line again and realised that it states a period from x date to 23rd April.

Does that mean I go back on 23rd or 24th? Can't ask HR as office is on hols Fri and Mon. (In Scotland, not sure if paperwork is standard across UK.)

24th.

Thanks!