Great site to visit Windsor and London.  Denham station with half hourly trains in to London Marylebone is only a mile and a half away and an off peak travel card giving you train and tube is very reasonable. It only takes 30 mins in to London. There is cheap car parking at the station.  The facilities are recently refurbished and are clean and warm.  Nice friendly and helpful wardens (it was relief wardens whilst we were there).  There is a good Indian Restaurant in Denham and they will deliver take aways to the site.   For a city break with the peace of the countryside to return to each day you can't beat it. (The aerodrome noise is only a problem during day light hours and to be honest we were out most of the day)