ClubSpark now has a feature that allows you to set a cap on bookings for your course, to ensure you don't end up with bookings beyond your capacity (supervision ratios, venue size etc.).
Log into ClubSpark, & click 'Programmes' on your club admin page as below
Select the programme you have, or are looking to set up
Once you have created/located your active programme, click anywhere on the field below to access your programme register, settings etc.
Select 'edit programme' in the top right corner
Scroll down & edit the 'capacity' field to limit bookings past a certain number.
Save the programme & the capacity will take effect.