Every dealership is different in what they ask for up front. Some want the entire AP and options, some are happy for you to pay 48hrs before handover. It’s completely up to them, not Motability.
If paying up front is an issue, if possible you could try a different ford dealership. It’s one of the first questions I ask when contacting a dealership these days as we were caught off guard when we chose a Mini, they wanted it all upfront but we couldn’t afford it. We had to save up before we could go back and order.