I agree with nistri that it is not a rare car. There are many available to buy ranging from £500 for a basket case up to £6-7,000 for a really nice example. The series 1 and 2 are rarer and i think more attractive to look at. I have a series 2 and regret getting LHD (as yours is). The car was orinialy designed to be RHD and the steering column on the LHD versions really makes maintenance items really complicated. Changing the dynamo and starter motor is virtually impossible without taking the engine out, and dropping the front exhaust section is also difficult.
Try and buy a RHD example and I strongly suggest you take a knowledgable Appia chap along to give it the once over. There are many pits to fall in when buying an unknown example. (I know as I fell in many with mine and see my post on replacing the timig chain). That said they are a delightful car with beautiful suspension and steering characteristics. They are a very underated Lancia. What is the asking price? Not above £6,000 I hope.
PS. One word of warning. If the car has been laid up for a while the brakes will need overhauling. This can be very expensive (£thousands if shot). Do not consider buying unless the brakes work 100% with no shudder or pulling,