You do not need a permit to park on the Open University campus.
Dedicated Visitor Parking (which is signposted) is available in front of the Berrill Building, near the entrance to the Open University campus from the V10 (Brickhill Street). It takes about five minutes to walk from the visitor car park to the Michael Young Building.
The closest car park is the South West Parking area opposite the Michael Young Building (and the adjacent Church Parking area). Please note that, although there usually are some spaces available, these may be full, in particular if you arrive after 9.30 am. In that case, the most likely places to find a space are the Visitor Parking area mentioned above or the East Parking (in particular the Overspill Parking) areas nearby.