Hi.
I have been a scheme member for 28-years now so I’d like to think I can answer your question from experience. Generally, bearing in mind all dealers can differ slightly depending on what they still need to complete their end, I would allow an hour from start to finish for the handover.
Dealers need to cross the T’s and dot the i’s paperwork-wise their end. They have to explain certain things to you, quickly check the old car you are returning before handover (if applicable in this case?), ask a few questions, etc etc and generally just go through a few formalities. You yourself need to check the new car you are taking delivery of before entering your all important pin number for damage/issues.
I don’t know about other Motability members – but personally speaking, I already know everything about the new car I am picking up – because I am very sad like that & would have done my homework extensively on the new car! I watch every video & read every article in order to know what does what, what’s this for, what’s that for! That saves me a lot of time on handover day because the Motability salesperson never needs to sit in the car with me and go through all the introduction faff.
So yeah, from personal experience, I would allow an hour. That’s more than ample in my case. Obviously your experience may well be a little different – bearing in mind the issues you state above – but try not to panic. Best of luck to you. Remember to upload a couple of photos of the car once collected!