Sorry for the large amount of questions this week 
i am trying a larger feature that is outside what i have done before. My question here is how to add the shader defines for a new light type for example in the shader i want to have a define for sphere light and one for tube lights. I believe iv added all the code to get the light working correctly so im not sure what im missing.
Look in Renderer.h, which has the shader sub-variation defines, and Renderer.cpp, which has string arrays for the defines, and functions like SetBatchShaders(), SetLightVolumeBatchShaders(), LoadPassShaders(). You will have to change the indexing, which is a bit errorprone.
Sounds fun that is likely why unreal treats each light type as a component
Well, you could add something like GetShaderDefines() to Light component, but at some point you’re going to want to get the actual shader variation needed by a light performantly, ie. without string manipulations / compares.
Do you think for know it could be worth having Area lights extend point lights in the same manor as unreal 4 rather then adding a new light type. I as this as the system for adding new light types looks way over my head currently.
If the area light calculations are more complex, I would hope that every point light would not run them.
It doesn’t have to be a new light type as such, but a new boolean / new shader define nevertheless.
Try to track how the NORMALOFFSET define was added, that was the last time when the light variation string array was being expanded.