Mrs S is on iPhone, I’m on Android and we really need a Calendar that we can both easily access, update etc. Any ideas on what works well across both platforms and shares well?

Both can sync with Google Calendar.

As GrahamS says, google calendar would be the best free option.

will give it a go, thanks

On iPhone you can add it as a CalDav account or just a “Google account”:

https://support.google.com/calendar/answer/151674?hl=en

google calendar

wife an i have that setup and it works well

(apart from her having to use the inferior iOS calendar settings!)

(apart from her having to use the inferior iOS calendar settings!)

Have a look at the fantastical app. Much nicer calendar than the rubbish one on iOS.