Orchid Society of Great Britain: 

http://www.osgb.org.uk/

South East Orchid Society: 

http://www.seos.care4free.net/

North of England Orchid Society: 

http://www.orchid.org.uk/

North Hampshire Orchid Society:

http://www.north-hampshire-orchid-society.org.uk/

Cheshire and North Wales Orchid Society: 

http://canwos.org.uk/

Bournmouth Orchid Society: 

http://www.bournemouthorchidsociety.org.uk/

Orchid Society of East Anglia (Norwich):

http://www.osea.org.uk

Fenland Orchid Society:

Facebook ‘Fenland Orchid Society’

Essex Orchid Society:

http://www.essexorchidsociety.org.uk

Cambridge Orchid Society:

http://www.cambridgeorchidsociety.btck.co.uk

Lee Valley Orchid Society:

www.leavalleyorchidsociety.com

American Orchid Society (good for culture advice):

http://www.aos.org/orchids.aspx

http://www.aos.org/orchids/culture-sheets.aspx