I have  a school booking in May and the very organised GCSE biology teacher has given me  a comprehensive outline of his aims for the visit.  He has asked me to demonstrate how we adjust the amount of water, light and heat that we give our crops in order to create a more efficient food chain!  So I have been standing in the muddy back paddock looking at the fog and sideways rain and wondering how to make the sun come out.  At least it's not snowing yet...