Thanks for the tip about the density filter. I keep forgeting about filters for some reason - too keen to play with the 'new' features I guess :) I'm not sure if this works from console (as your image suggests you were doing.) I was testing with an external .py file, and just reloading it after each edit. Another possibility is if the light is inside the solid part of the bollard. The bottom cylinder in my example was 25 units high, with 5 unit glass and 5 unit cap. So an offset of +27 in SetPosition puts the light near the middle of the glass. Also I set direction to surface at 0 (vertical) so I wouldn't have to take angles of rotation into account either.

Mark