Hello and welcome to WAB!
Yes I'm a member of the "Friends of Crossness Nature Reserve" and am usually there at least once a month. It's not an RSPB site by the way, it's owned and managed by Thames Water. All the web sites, including Thames Water's own, are out of date as they still have Karen Sutton as the reserve warden. Karen left last year to join the Lea Valley Regional Park. At the moment the warden is Jane Clarke who is on loan from the London Wildlife Trust. You could try emailing Jane at
Jane.Clarke@thameswater.co.uk.
Good news about the red kite! I know there about because other people keep seeing them but I haven't seen one myself yet.
Dave P.