Looks excellent from your post but it doesn’t work for me in Windows. After I draw the polygon and select “Download OSM Data” again I’m asked where to save the OSM file, the layer disappears from the layer panel and if I look at the log message it says:

GDAL execution console output FAILURE:

		Unable to open datasource `papers.gpkg' with the following drivers.
		
		  -> JP2ECW
		
		  -> OCI
		
		  -> SOSI
		
		  -> PCIDSK
		
		  -> netCDF
		
		  -> JP2OpenJPEG
		
		  -> PDF
		
		  -> DB2ODBC
		
		  -> ESRI Shapefile
		
		  -> MapInfo File
		
		  -> UK .NTF
		
		  -> OGR_SDTS
		
		  -> S57
		
		  -> DGN
		
		  -> OGR_VRT
		
		  -> REC
		
		  -> Memory
		
		  -> BNA
		
		  -> CSV
		
		  -> NAS
		
		  -> GML
		
		  -> GPX
		
		  -> LIBKML
		
		  -> KML
		
		  -> GeoJSON
		
		  -> Interlis 1
		
		  -> Interlis 2
		
		  -> OGR_GMT
		
		  -> GPKG
		
		  -> SQLite
		
		  -> ODBC
		
		  -> WAsP
		
		  -> PGeo
		
		  -> MSSQLSpatial
		
		  -> OGR_OGDI
		
		  -> PostgreSQL
		
		  -> MySQL
		
		  -> OpenFileGDB
		
		  -> XPlane
		
		  -> DXF
		
		  -> Geoconcept
		
		  -> GeoRSS
		
		  -> GPSTrackMaker
		
		  -> VFK
		
		  -> PGDUMP
		
		  -> OSM
		
		  -> GPSBabel
		
		  -> SUA
		
		  -> OpenAir
		
		  -> OGR_PDS
		
		  -> WFS
		
		  -> HTF
		
		  -> AeronavFAA
		
		  -> Geomedia
		
		  -> EDIGEO
		
		  -> GFT
		
		  -> SVG
		
		  -> CouchDB
		
		  -> Cloudant
		
		  -> Idrisi
		
		  -> ARCGEN
		
		  -> SEGUKOOA
		
		  -> SEGY
		
		  -> XLS
		
		  -> ODS
		
		  -> XLSX
		
		  -> ElasticSearch
		
		  -> Walk
		
		  -> Carto
		
		  -> AmigoCloud
		
		  -> SXF
		
		  -> Selafin
		
		  -> JML
		
		  -> PLSCENES
		
		  -> CSW
		
		  -> VDV
		
		  -> TIGER
		
		  -> AVCBin
		
		  -> AVCE00
		
		  -> HTTP

2017-07-05T17:23:19 0 GDAL execution console output FAILURE:

		Unable to open datasource `papers.gpkg' with the following drivers.
		
		  -> JP2ECW
		
		  -> OCI
		
		  -> SOSI
		
		  -> PCIDSK
		
		  -> netCDF
		
		  -> JP2OpenJPEG
		
		  -> PDF
		
		  -> DB2ODBC
		
		  -> ESRI Shapefile
		
		  -> MapInfo File
		
		  -> UK .NTF
		
		  -> OGR_SDTS
		
		  -> S57
		
		  -> DGN
		
		  -> OGR_VRT
		
		  -> REC
		
		  -> Memory
		
		  -> BNA
		
		  -> CSV
		
		  -> NAS
		
		  -> GML
		
		  -> GPX
		
		  -> LIBKML
		
		  -> KML
		
		  -> GeoJSON
		
		  -> Interlis 1
		
		  -> Interlis 2
		
		  -> OGR_GMT
		
		  -> GPKG
		
		  -> SQLite
		
		  -> ODBC
		
		  -> WAsP
		
		  -> PGeo
		
		  -> MSSQLSpatial
		
		  -> OGR_OGDI
		
		  -> PostgreSQL
		
		  -> MySQL
		
		  -> OpenFileGDB
		
		  -> XPlane
		
		  -> DXF
		
		  -> Geoconcept
		
		  -> GeoRSS
		
		  -> GPSTrackMaker
		
		  -> VFK
		
		  -> PGDUMP
		
		  -> OSM
		
		  -> GPSBabel
		
		  -> SUA
		
		  -> OpenAir
		
		  -> OGR_PDS
		
		  -> WFS
		
		  -> HTF
		
		  -> AeronavFAA
		
		  -> Geomedia
		
		  -> EDIGEO
		
		  -> GFT
		
		  -> SVG
		
		  -> CouchDB
		
		  -> Cloudant
		
		  -> Idrisi
		
		  -> ARCGEN
		
		  -> SEGUKOOA
		
		  -> SEGY
		
		  -> XLS
		
		  -> ODS
		
		  -> XLSX
		
		  -> ElasticSearch
		
		  -> Walk
		
		  -> Carto
		
		  -> AmigoCloud
		
		  -> SXF
		
		  -> Selafin
		
		  -> JML
		
		  -> PLSCENES
		
		  -> CSW
		
		  -> VDV
		
		  -> TIGER
		
		  -> AVCBin
		
		  -> AVCE00
		
		  -> HTTP

2017-07-05T17:24:21 0 GDAL execution console output FAILURE:

		Unable to open datasource `papers.gpkg' with the following drivers.
		
		  -> JP2ECW
		
		  -> OCI
		
		  -> SOSI
		
		  -> PCIDSK
		
		  -> netCDF
		
		  -> JP2OpenJPEG
		
		  -> PDF
		
		  -> DB2ODBC
		
		  -> ESRI Shapefile
		
		  -> MapInfo File
		
		  -> UK .NTF
		
		  -> OGR_SDTS
		
		  -> S57
		
		  -> DGN
		
		  -> OGR_VRT
		
		  -> REC
		
		  -> Memory
		
		  -> BNA
		
		  -> CSV
		
		  -> NAS
		
		  -> GML
		
		  -> GPX
		
		  -> LIBKML
		
		  -> KML
		
		  -> GeoJSON
		
		  -> Interlis 1
		
		  -> Interlis 2
		
		  -> OGR_GMT
		
		  -> GPKG
		
		  -> SQLite
		
		  -> ODBC
		
		  -> WAsP
		
		  -> PGeo
		
		  -> MSSQLSpatial
		
		  -> OGR_OGDI
		
		  -> PostgreSQL
		
		  -> MySQL
		
		  -> OpenFileGDB
		
		  -> XPlane
		
		  -> DXF
		
		  -> Geoconcept
		
		  -> GeoRSS
		
		  -> GPSTrackMaker
		
		  -> VFK
		
		  -> PGDUMP
		
		  -> OSM
		
		  -> GPSBabel
		
		  -> SUA
		
		  -> OpenAir
		
		  -> OGR_PDS
		
		  -> WFS
		
		  -> HTF
		
		  -> AeronavFAA
		
		  -> Geomedia
		
		  -> EDIGEO
		
		  -> GFT
		
		  -> SVG
		
		  -> CouchDB
		
		  -> Cloudant
		
		  -> Idrisi
		
		  -> ARCGEN
		
		  -> SEGUKOOA
		
		  -> SEGY
		
		  -> XLS
		
		  -> ODS
		
		  -> XLSX
		
		  -> ElasticSearch
		
		  -> Walk
		
		  -> Carto
		
		  -> AmigoCloud
		
		  -> SXF
		
		  -> Selafin
		
		  -> JML
		
		  -> PLSCENES
		
		  -> CSW
		
		  -> VDV
		
		  -> TIGER
		
		  -> AVCBin
		
		  -> AVCE00
		
		  -> HTTP

Data has been downloaded and saved into the OSM file.

I’ve been thinking of doing something similar for a while, would help where I could. My plan was to eventually replace the OS maps I am going to be using on a future website that will in the short term be using OS maps.

I looked into this a few weeks ago before the meteorite after seeing all those Russian road accident videos on YouTube and thought it would be a good way to record data. There is a Video Mapping Plugin for JOSM which sort of worked with a GPX file recorded at the same time.

The plugin was very unstable though, crashed JOSM regularly and then disabled the plugin on restart. I also couldn’t resize the video, it always started small and while I could resize the window the video stayed the same size. I wasn’t using the latest .6 version because that hasn’t been released to the public.

It’s worth looking into and it did help mapping for instance exact locations of bus stops, benches, businesses, field boundary types and far easier than tagging with a phone/GPS.