A deposit may be asked for by the dealer, “may be asked” is the important bit, it’s not a Motability requirement so you’re free to refuse and order elsewhere if needed.
Never been asked for a deposit yet though others have been. Personally I wouldn’t do it, I find most dealers as honest/reliable as a 25p Mickey Mouse genuine Rolex, but then again I’m a grumpy old man (apparently!) 🙂
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!