CSE3520 - How the conditions are to be interpreted: Number of members and memberships: What are “qualifying supplies”?

You should check the other guidance available on GOV.UK from HMRC as Brexit updates to those pages are being prioritised before manuals.

‘Qualifying supplies’ are services which are ‘directly necessary’ (see CSE3720) to enable a member of the CSG to engage in the exempt and/or non-business activity for which the services are supplied.

Revenue and Customs Brief 10 (2018) explains HMRC’s revised approach to the test for directly necessary services.