It appears that virtually all Wordpress GPX plugins are now not being supported unfortunately - the one I really wanted to work is WP-GPX-Plugin but that is no longer supported and now appears to always display the elevation overlay on top of the speed which as I am sailing is rather pointless!
I've tried embedding the share link from Garmin Connect in iframe which works fine but unfortunately it doesn't display the speed graph underneath with the interactive slider.
Also to remove things like calories and elevation?
There must be some way of adding flags / variables to make changes to what is displayed?