So I asked the chap who gave me the test drive about lead times. He said they always say 20 weeks maximum, to avoid disappointment, but he's never known it to actually take that long.
Now I placed my order in wk 17, and I'm currently quoted wk 37 estimated build. That is 20 weeks, and that's not including shipping, so as far as I can see my car is currently scheduled to take longer than what my dealer considers the absolute maximum lead time before it is delivered.
Unless the estimated build comes forward. Based on the original estimates from the dealer I ordered at, my car should have been built around wk 28-30 so something has gone very wrong somewhere for them to now tell me I'll be waiting another 2-2.5 months for it!!!!!