How to remove reading lamp

[Silverman]

Hi all, I want to replace this reading lamp, but can't work out how to remove it. No visible screws or allen bolts. Tried to unscrew the base but doesn't want to move, so thought I'd ask here before trying more force.

 

[Silverman]

I have had a reply from the Devon conversions forum. So if it helps anyone else, the white plastic piece slides left and right to reveal two screws.

 

[Silverman]

In case it might help someone in the future