Is it because they changed the pressings at the rear (no vertical swages) or did they think the RP looked better balanced with a smaller rear?
Dave.

Location: Sheffield

Late RNs had no external swages, but still had the wide body. They also got the RP type instrument panel, rear tank and four speed engine/gearbox. It doesn't answer your question, just adds to the mystery!

Robert Leigh

Location: Cottenham, north of Cambridge

Where's Dave Mann when you want him ? !!!!!!!!

Maybe the gentlemen at Longbridge worked out that the Great Depression had reduced the waistlines of their potential customers and made a car to fit?

Location: Fishbourne near Chichester

You may think an inch or so is insignificant for most things (note that I said for "most" things) but I think the RP is better looking from the rear than an RN. What am I saying! Sorry Mr Dave Mann.
Dave.

Location: Sheffield

I'm here and no I don't know why the RP rear is narrower. The RP might be later but it was inferior, no double dip headlights, the vacuum wiper isn't so good with the 26Va, a four speed gearbox that was little better than the 3 speed except for going up the side of your house and that instrument panel with the combined ignition/light switch leaves something to be desired. Or maybe I'm just biased, the early 4 speed crash gearbox which nobody wants is almost indestructible.

Early RPs did have double dip headlights. The change came in '33 but I don't know when.

Location: Cottenham, north of Cambridge

Stuart Joseph will be able to answer that Robert.

Thanks Dave!
Having been working with A7's since 1964 I have met a number of people who worked on the line at Longbridge and the one comment they all made was 'never say that part wasn't fitted to a particular model'.
1933 saw the change over from the RN to the RP and I have always associated the fitting of the Lucas LB130 headlamps with the RP. However as is common with current manufacturers there may well have been 'run out' period when old stocks were used up and I don't doubt that a number of RP's left the factory with Lucas 32/35 headlamps as fitted to the RN.
Regards
Stuart

Location: Staffordshire, the creative county