Can not clear browsing history on iPad

I am unable to clear Safari's browsing history on my son's ipad. I have turned off Content & Privacty Restrictions, turned off Screen Time, stopped syncing Safari over icloud, there is nothing to delete from the Reading List, I have blocked cookies, I have restarted the device and I have reset Settings. Nothing makes any difference; the 'Clear History and Website Data' is still greyed out. I am told that the next step is to erase the device and start from scratch but, for obvioius reasons, I would rather not do this. Does any one have any other suggestions or is really the case that the iOS is so convoluted in design that a simple function such has this has become unworkable on ipads? Thank you in advance.