Converting a Lima Class 55 into a porterbrook Class 55

[wilwahabri]

I am in the process of converting a Lima class 55 to the Porterbrook specification. I have removed the existing moulded lights from the ends but now need to replace them with the Wipac units as fitted to the Porterbrook diesel. these appear to be running from outside in, marker, rear and high intensity headlight. The marker and rear lights being slightly smaller than the headlight which looks to be a 7" car type light. I need a set of dimensions to work to, based on my assumption that the Headlight is a 7" unit and then assuming the other lights are 6" I would guess at about a 21" x 8" lamp unit, which scaling to 4mm scale would make this unit 7mm long by 2.7mm high. could anyone provide me with the size of the actual unit and lights or confirm my assumptions please?