Repairing roof lights on Scalextric Police RR

[Fun Bus]

One of the blue roof lights on my Son's Police Range Rover isn't working. Now he loves it despite this as a 5.5 year old would but I'd like to repair it / have it repaired. As much as I just want to take the body off and have a tinker I'm worried about causing more damage through 'having a go'. Any advice on how to approach it (if anyone has done before) or whether a model shop in Nottingham offers a repair service of any sort?

Thanks in advance.

[Fun Bus]

Russell, belated thanks for your help and advice. I sent it back to Hornby who repaired and returned quickly back to me so all good.