Thanks Rob,
The studs I was referring to are fixed to the back of the light panel at the extreme corners of the number plate window. The four inner ones are a nominal length to hold the retainer strips.
I have assumed the extra length is to accommodate a short length of tube to allow the number plate panel to be set further back for more light to come from the sides. But I have none of these parts, albeit easy to replicate if I know what is correct. I should clarify that it is a '48 Mk IV.
