Fiona, I've just checked my (Android) app and all is working as usual. 

Below is a screenshot of my 'Settings' options. Perhaps you could compare and let us know what options you don't have? 

In any case, my inexpert suggestion is to delete the app, then reinstall it. Any routes you have already saved will be there when you reinstall the app. 

Thanks for your suggestion Hobbesontour. Ive just tried that but still the Offline maps option is not showing! I can only assume that my phone is non-compliant. About to set off into the N Yorks moors where signal is v poor. As fallback I've downloaded offline google maps so hopefully will not get lost. 

There was a previous report of this: https://cycle.travel/post/5643 (see the bottom comment/screenshot)

It looks like a very few Android phones don’t show “Offline map” in the menu and I have no idea why. Certainly the app tells the phone to show the option. (Android is full of little inexplicable gotchas like this…)

Do you have a blank space in this spot in the menu, and can you tap on that?

I did look to see if anyone had previously reported this wrinkle but failed to find that post. As you suggested, I have a blank space and clicked on it and lo! the map appeared. Thanks so much for your help. I think this app is brilliant and will recommend to my cycle riding sons.

Great! It is the strangest thing that it doesn’t appear… I haven’t yet been able to find out why but will keep digging.