For what must be going on 18 months I've become more and more frustrated by the official iOS OSMaps app and it taking up to a minute to initially render even offline content. In chatting to friends, and indeed Mrs Hyppy, I know this isn't only affecting my usage. While OSM (via Organic Maps, or Talkytoaster) is nice, I do like my OS Mapping too and had been looking to alternatives means to access the maps when my subscription came to renew. It looks though, that last week's v.5.x release has finally fixed the rendering bug so if you're having problems and haven't updated, give it a whirl.

Old (left) and new (right) map view shown here as a quick check to see if you're updated. (Layout rather than UI elements' colour as adding a dark/light mode seems to be a new feature).

I'd noticed the app on my phone was working a bit better (much less crash prone) but I couldn't bear the thought of updating and losing all my downloaded maps, which is what happened the last time.
'spose I've no choice really...