-
I don't think you have a recalc the route option on the phone. You can make the app draw a route to you to some given address (it automatically syncs it to the device) but it's pretty shit in that regard. To do a proper route you'd have to whip up Komoot / RWGPS (the mobile apps...) and make the updated route there and sync that (which involves tethering the phone) and it all needs decent connectivity too, especially if you have lots of routes in various services like I do, as the 3rd party "Sync" option will sync each and every one and it's kind of slow even with good home broadband. So rather than all the fiddling roadside I always opted for a quick zoom-out and find my way to the route that way, of course as mentioned above that might be pretty hard in city traffic with all the no-go zones and one ways.
I'd go for the Roam for the auto-routing, but if the budget is limited the Bolt is livable with (would be PITA in an unknown urban env). The maintenance closures/diversions aren't a problem with the Roam as you miss the route it will keep recalculating and give you the next alternative.
Extra £100 as opposed to which model? It was my first Wahoo, used it for a good while, I think it's good enough, provides zoom levels. But if you get lost you need to find the way back (or connect to the route upstream) yourself. But zoom (zoom out this time) still works (can't pan...) you can kind of work out which direction you need to go. Screen updates faster compared to bigger screen Wahoo models (due to all of them being e-ink, small is faster) so overall the unit feels snappier too. And the buttons feel much nicer compared to the bigger models. (I have experience with all three, switched to a mate's older ELEMNT when the Roam order got delayed and I had already sold my Bolt)