Monitor Arm (Finchley Road Station NW3)

It's an Amazon Basics model (search for "Amazon Basics Gas Spring Single Computer Monitor Arm" on the US Amazon store). VESA compatible. No drilling necessary. Attaches to the desk through pressure (see photo).
Pickup either around Finchley Road Station (weekdays in the evening, or weekends) or around Liverpool station (weekdays during work hours).

Fair Chance Policy: I’ll wait before choosing a recipient to give more people a chance to reply.