Scooter - RHD scooter combos in Italy - bathtub tom

I happened to see a 1950's picture of a Lambretta combo in Italy with the bike on the right. I thought it was strange and then I found one of a Vespa combo, also in Italy with the bike on the right.

Anyone have any idea why?

Scooter - RHD scooter combos in Italy - RT

Vespa's had the engine alongside the rear wheel, can't remember which side, so that probably influenced the choice of sides.