Clean smart casual and appropriate for the occasion. (As would be defined by a majority of reasonably minded people)
NB: Beach style Flip Flops are not permitted.
Any recognised golf clothing/shoes. (If you are unsure about your golfing attire, a good indicator to what is acceptable is any clothing/shoes that can be purchased in the Pro Shop)
Mobiles phones should be switched off, both on the course and in the clubhouse.