Errors in Bar Numbering

Apologies for repeated posts, but my latest problem with imported MusicXML (from Photoscore) is seemingly a result of Dorico not registering multiple bar rests.
When I add the bars back in, the subsequent bar numbering keeps jumping back (it would seem) to the number the bar would have been before adding back the multiple bar rests. Is there a simple way of recalculating the bar numbers for the whole flow in one go - rather than do (over 600!) bar number changes one by one?

In Dorico, barlines, time signatures and bar numbers are all connected. If things are working correctly then the presence of a time signature (e.g. 4/4) tells Dorico to put an implicit barline every four crotchet/quarter beats, and increment the bar number by one each time it draws an implicit barline.
It sounds like what’s happened here is that your MusicXML file has imported with an opening time signature that is impotent. Each subsequent barline is an explicit barline, drawn with its own hidden time signature and an explicit bar number change. You need to get rid of the explicit time signatures by deleting them (or their preceding barlines) - turning off the Signposts doesn’t solve the problem; it just makes it less visible.

One quick way to fix this is to turn off the time signature signposts - do leave the others on - then Select All (not using the System Track - the System Track will select barlines and you really don’t want those) - then copy and paste to a new flow.

Obviously, the original XML file contains unnecessary garbage (time signatures, explicit bar numbers).
I’d recommend to create a new flow and simply copy and paste the scanned music into it. I always do this with XML sources (Sib or Photoscore). Personally, I like to prepare this empty flow with things like the expected number of bars, key and time signatures, tempo, and rehearsal marks, before pasting in. It’s faster and more reliable than cleaning up the XML mess, especially from Photoscore.