Maybe PPR entry is due to what appears to be limited apron space and a cursory measure to avoid a sudden influx of unexpected aircraft causing congestion.
Out of interest Dick, did you make a call to see if it would be ok? Personally I've never been knocked back by an airport saying PPR in their ERSA entry. Mine site strips though are a different beast. You need to have at least 10 space shuttle landings in your log book and $1.2Bn liability insurance.