The scenario is that a car manufacturer wants to produce a new design of vehicle that hasn't been done before. He has existing plant, factory and manufacturing process, and engineers that he can use, but the car will look and work significantly differently to his current models. He wants to build a prototype to see if it will work - with the aim of putting it into production. How long would building the prototype take? Is 6 months realistic? Too long, too short? And what would the likely cost be? (ballpark figure is fine).
I don't need to go into huge detail as long as people reading the story don't go "HUH? It took one week and cost ten pounds? I don't think so!" - I'm exaggerating, but that's the kind of thing I want to avoid!!!
I'm not talking about building a non-working concept car. This is supposed to be a production intent prototype.
The book is set in the UK, 80 years in the future, after an environmental catastrophe that has changed the face of the planet. I don't think any of that has any bearing on the question - I'll adjust for what I think is likely inflation/deflation in cost. I just want to know what's likely now and can extrapolate the rest to suit my story.
I've done quite a bit of reading and research online but it's such a specific enquiry, it's hard to find out for sure. I have searched 'building a prototype car' and 'cost of building a prototype car' but beyond some background reading, I haven't found anything that comes close to answering the question.