I would like to protect against hotlinking using the .htaccess file but this is now deprecated. It appears that no alternative has not been posted so is anyone able to suggest a method please?

If you are referring to https://github.com/zenphoto/unsupported-misc/tree/master/htaccess-against-hotlinking that should still work. Thte htaccess things regarding this as far as I know didn't change.

Thanks @acrylian