dd/mm date format on android in xlsx files

I'm just starting to use mobile documents using google sheets but am struggling with date formats. I am in the UK so use dd/mm/yyyy in excel, but when files are saved to drive and opened in sheets on android, the dates are displayed in mm/dd format. I can reformat how they're displayed in sheets, but the underlying data (including new entries) is still in mm/dd. I've read about changing locale but it seems this is only able to be done on the desktop. If I open the files this way I get a sheets version of the file alongside the XLSX version, which I want to retain because it contains macros and some users have only just mastered windows...