At the risk of repeating the very good points already made;
1) Motability always ask customers far too much for ex-lease cars. You would get better value buying from a dealership (price and spec).
2) Dealers will always negotiate asking prices and you will always get a warranty. Motability won’t negotiate and you don’t get a warranty. Cars are a bit like shares. Past performance is no guarantee of future success!
3) Hindsight is a wonderful thing, but sacrificing PIP for 5 years to just drive 16k miles is an extremely expensive route to car ownership. At that sort of mileage I would be running a private car, which doesn’t have to be a brand new one
4) You won’t have to pay road tax.
A few additional points;
1) That insurance price seems very high. Are you very young / live in a high risk area / assuming that the prang will result in no NCD? A few years ago I ran a brand new £41k BMW 5 Series and my fully comp insurance with protected NCD was £300. If it’s the prang, the second and third year will be substantially cheaper. I use Compare the Market for both my daughters car insurance policies. No risk whatsoever in using them and you will get much cheaper quotes.
2) Most car dealers will discount the MOT cost if done at the same time as the annual service.
3) Many dealers include 12 months break down cover free of charge after having the car serviced with them. If not, Green Flag are a lot cheaper than AA / RAC.
4) £13,200 is a chunk of cash for a 5 year old car. You could get something quite decent in the second hand market for that and it is unlikely that you’d have as much go wrong as you are budgeting for.