Hi Phil,
The "toll gantry" is not one of my additions.  I guess it was already there on the service road - which I did adjust slightly, following the aerial-view in the editor.  The road needed to be re-aligned when I added some buildings there.  I strongly suspect it's an error!  As far as I know this is just a private access road for farm buildings and a holiday cottage. I can't see anything like a "gantry" of any kind on any map or satellite view. 

I didn't notice the toll gantry when the edit was done. In fact it's the first time I've seen that tag, but I'm still relatively new to OSM!   

Best regards, Geoff.