This warning came up on my dash this evening...'LIGHTS'...checked all my lights and they seem to be fine...i'm assuming it's a brake or reverse light but i haven't checked yet...

 

also...the battery light is slightly on when i drive...but seems ok. not sure why this is.

'LIGHTS' is the Stop/Tail lamp out warning.

 

It's not a Battery warning lamp, it's a Charge warning lamp, which measn there is a potential fault in your charging ciruit, get it checked over by a competent auto electrician. Some battery specialists will have the proper piece of kit to do this. If you have a Bosch centre near you they'll do it for you. Incidently, none of them should charge you for this ;) (please excuse the punn!)

 

HTH