a) a performance of morris dancing or any dancing of a similar nature or a performance of unamplified, live music as an integral part of such a performance, or
(b) facilities for enabling persons to take part in entertainment of a description falling within paragraph (a)."

Richard you are the lawyer and I am not. But surely to place the interpretation you state for it - it should read?

a performance of morris dancing or any dancing of a similar nature AND a performance of unamplified, live music as an integral part of such a performance, or.........

The use of the word OR gives three different - if connected activities that do not require the licence?