Project 'Green' House #1: LED replacement lighting for circular fluorescent tubes // DavidJB.com // Python, Technology, Web, Linux, and more, by David Beitey
Crompton Cir40spww 16 Inch Circular Fluorescent Tube 40w White : Amazon.co.uk: Lighting
Havells Sylvania T9 Circline Plus Circular Fluorescent Tube 22W 4 Pin G10q 3000K - John Cribb & Sons Ltd, UK Electrical Distributors, Dorset, Hampshire, Wiltshire, Somerset & the Isle of Wight.