If you use Jedi or e2m3u2bouquet it will generate a file for EPGimporter which can then be used to update both the IPTV through this file and if you enable the UK freesat source option in EPGimporter then you can update all in one go.
Obviously if you are currently not using either of these 2 plugins then you may have to learn how to do it, but its better than blindly doing what the provider says to do (it will only be in their interest)