I've seen plenty of examples of Bat & Chalwyn lamps where the lens colour does not match the body colour, green body colours with red or clear lens colour and yellow bodies with clear amber or red lenses etc. The photos on Richard's UK web site do show Chalwyn & Bat lamps where the body colour and lens colours do match so perhaps it was up to the customer to nominate the body colour and the lens colour. It would be interesting to find out just what application dictated a particular body colour, perhaps someone else can help here? Red & yellow were certainly used in roadworks applications but green & blue?
Green lenses were used in Australia with red bodies but in a very limited way, the human eye's peak spectral sensitivity is in the green region so my guess is that someone thought that this would be more detectable, again does anyone else know why certain colours were used for the lens?
best regards.... Frank