Files I used to make the constituency cards
The geo files I've shared here are the constituency files for the whole UK with all the underlying data attached. I've shared it in Shapefle, geojson and GeoPackage format. The original data I sourced from ONS and Ordnance Survey (as it says on the final outputs) but I noticed a lot of the previous mapping didn't show Northern Ireland's large loughs so I fixed that and chopped them out. It just didn't seem right looking at Northern Ireland completely filled in. These files are quite big so if you are using then on the web you might want to try a generalised version instead (which you can easily create using Mapshaper).
I've also shared a simple csv file, without any geodata attached.