UKC

Well, is there?

As I don't live in the UK I've never looked at the OS's apps, but is this the sort of app you're looking for

https://ignrando.fr/boutique/applis-mobiles-outdoor

?

You can get the 1:25,000 IGN maps of the French Alps in Viewranger - and just purchase the tiles you need.

Same for Anquet maps

... and for Gaia GPS.

I think, these days it is not so much about what maps you can get for your app, but how easy they are to use and how greedy they are on the battery.

And Memory Map.

You can get whole of France at 1:25,000 for £150 at moment, and use across 4 devices.  You can store all the mapping on a micro-sd on your phone (file is about 16 GB).

+1 for view ranger. Helped us get down the valle blanche in a white out. 

http://iphigénie.com/

This gives you you slope angles (very useful for avalanche avoidance) which I dont think the others do.

another for iphigénie use it all the time living in the alps.

cheers

150 quid?? iphigenie is 14.99 euros/year.  Sounds like a bit of profiteering going on

It is the whole of France, no further subscription, usable across 4 devices. Can store the whole of France on your phone in a 16 GB file.

We bought it a good few years back and its been good to have direct access on two phones and PCs.