How do you only show one service for booking in Appointments+?

Hi guys,

This is a fantastic plugin and its working well for us. Just want to know if it's possible to only display one service to be booked instead of all of them in the dropdown.

I have searched the shortcode functions and it looks like there may be a way to only show services from specific workers but I haven't got that to work yet. The code I've been using is:
[app_services select="Book Your Next Meditation Session:" show="Show available sessions" worker="3"]

Worker 3 has been assigned just to one service "LIG Executive meditation" but it still shows up with our other service.

Can you help?