Since no-one has answered I'll throw in a couple of observations, not specific to the app - I'm on android.

Why not test it out at home?

And then some more. Not just if you can follow a preloaded route but what happens if you go off course (because of an unforeseen diversion?) Offline.

In the event of a serious change of plans can you create another route on the fly? Or load a second route that you prepared? Offline.

In my experience of online planning and electronic navigation of a bike route it's far more comfortable to be familiar with as many aspects of the functionality of an app as possible. Especially when it comes to online and offline functionality. We can plan to always be able to go online but that isn't always possible. Thunderstorms, I have found, are a common time to lose my data connection.

 I don't understand the technology but I believe that having WiFi on (if not connected) can improve the accuracy of my location. Ditto with data so there may be an accuracy issue with using Airplane Mode. Similarly, it's worth checking if activating Airplane mode may disable the gps functionality of your phone altogether - but that is something that could be manually switched back on. I'm pretty sure that one of my old Android phones did this.

There are so many possibilities for people with the same phones and operating systems to have different settings applied that often a one-answer-for-all can be misleading. Far better to figure out for ourselves.  

Quick followup (sorry, I’ve got a bit behind with forum messages). Yes, if you download the offline mapping, load your route, then go into airplane mode, it’ll still give you directions just fine. It won’t reroute you if you go off-course but otherwise it’ll be ok.

I’d like to add the ability to ‘sync’ routes from the site to the app, so that you can call up previously-downloaded routes even when you’re offline, but that’s in the future for now.

To go slightly off topic, Richard, can you confirm or deny my suspicion that gps accuracy is affected by one, other or both of cellular and wifi being deactivated?

Thank you

It’s not so much accuracy as speed of getting a position, I think. A phone uses the known locations of cell towers and wifi networks to get a first handle on the position. Without that it needs to get a signal from more GPS satellites, which can take time and be less reliable if there are high buildings or tree cover. 

Its a pity that when you save a route, it does not automatically save it on your phone as an offline download.

Brilliant app in every other respect by the way!

It’s on the way - probably one of the first features once I’ve got the Android app done!

(Though right now we have a power cut so no work on anything for the next few hours…)