Some links that you may find useful:
You might find some of the following links useful, but I'd like to point out that I'm not responsible for the content of any of these websites and nor do I necessarily endorse any views expressed within them.
Organisations
Bat Conservation Trust: http://www.bats.org.uk/
British Dragonfly Society: http://www.dragonflysoc.org.uk/
Butterfly Conservation: http://www.butterfly-conservation.org/index.php
Defra: http://www.defra.gov.uk/
English Nature: http://www.english-nature.org.uk/default.asp
National Trust: http://www.nationaltrust.org.uk/main/
RSPB: http://www.rspb.org.uk
Wildlife Trusts: http://www.wildlifetrusts.org/
Woodland Trust: http://www.woodland-trust.org.uk/
Wild about Britain: http://www.wildaboutbritain.co.uk
Wildfowl and Wetlands Trust: http://www.wwt.org.uk/
Places to visit
Bedgebury Pinetum: http://www.bedgeburypinetum.org.uk/
Felinwynt Butterfly and Rainforest Centre: http://www.butterflycentre.co.uk/
Gigrin Farm: http://www.gigrin.co.uk/
Alana Ecology: http://www.alanaecology.com/
Country Innovation: http://www.countryinnovation.co.uk
Warehouse Express: http://www.warehouseexpress.com/
Local Groups
Kent Bat Group: http://www.kentbatgroup.org.uk/index.html
Sevenoaks Wildfowl Reserve: http://www.kentwildlifetrust.org.uk/index.php?option=com_content&task=view&id=191&Itemid=307