Either get a service from Doncaster and they'll ask you to freecall Netherthorpe or approach from the west below Doncaster's airspace.
Call the office for PPR and a briefing. At this time of year the field can be very muddy. It's not unknown for circuits to be banned and even the airfield to be closed to all movements (happened Sunday before last IIRC). The friendly office staff will let you know.