Champions League Qualifiers changes

the scheduled events are things being hosted in UK - in same document you need to look here and in section 39 and the bit about a domestic elite sportsman and c (i) where it all looks covered ok for them to be exempt.

www.legislation.gov.uk/uksi/2020/568/schedule/2/2020-08-22

for anyone not want to enjoy the doc - it says elite athlete (and BBL is in that category) is exempt where:
has departed from or transited through the non-exempt country or territory in order to participate in an elite sports event and has returned to England with the intention of continuing activities as a sportsperson