The following clarification was issued after consultation with the judges following a question raised by an entrant:
Flowers and foliage in an arrangement do not need to be grown by the exhibitor.
Oasis may be used in our show although the RHS and NAFAS are now encouraging us all to use alternative methods in designs and there are many examples on the internet eg Pinterest .
There are guidance rules in the full schedule here. https://www.frenchayflowershow.com/wp-content/uploads/bsk-pdf-manager/2023/06/2023-Full-Programme-V11-for-website.pdf