I think it was just the leasing company giving an unrealistic time scale to be honest.
When I first enquired about ordering it they told me I could have a black from 'stock' that would be available in 4 weeks so I decided to go with that as I wasn't really fussy on colour.
2 weeks after I ordered the car I got given an anticipated delivery date to dealer of 17/12/15 then Monday just gone I got another saying 03/01/16 and then I got another email on Monday saying I could collect it this week, or they can deliver it in January - So I have gone for the collection and its turned out that I will be collecting it 5 weeks from date of ordering.