I've written about this gate here:

https://www.reddit.com/r/openstreetmap/comments/1qxa58h/how_should_this_gate_in_sheffield_be_tagged/

Here's a summary:

From some photos I've seen, it looks like the gate there for vehicles, and bicycles and pedestrians need to go around it. I've seen photos of a trail around it, but also of a cycle barrier right next to the gate. Some of the photos have the gate as yellow; others grey.

Seems to me that the gate could be tagged as for vehicles only, private, and usually locked. And assuming the cycle barrier is still there, add that as a separate way, with a cycle barrier node on it.

The cycle barrier:

barrier=cycle_barrier
cycle_barrier=tilted
access=no
bicycle=dismount
foot=designated (or perhaps just yes)

The gate:

barrier=gate
access=private
locked=yes
colour=yellow
