I'm afraid I don't have any particular wisdom on Wimbledon Park primary school, but I would encourage you to call the Council to discuss where people in your road have got places in the previous years. In my experience the schools team are very willing to help and will have the most up to date information. I realise that we are talking about two boroughs and that complicates matters.
I would also encourage you to fill all 6 places on your form. There are obviously many benefits from your child attending the closest school, but I do know of occasions when people have refused to list more than one or two choices and then perhaps understandably have been given a place absolutely miles away. I don't know exactly where you are, and I don't underestimate how stressful it might be to receive a place a little further away, but I would encourage you to fill the list to ensure that even if you were to wind up on the waiting list for WPP, that you have a school relatively nearby in the meantime.
Bit of a waffle, but I hope that helps!