Red Kites in Lincolnshire Wolds?

My wife came in from walking the dog to say she was sure she saw Red Kites where we live.  Went out with binoculars and there were five possibly six birds circling above us.  We often see buzzards but these birds  had forked tails, they did not call like our buzzards usually do.  Looked in the identification books we have on b9irds and could only find Red Kites that had description of what we saw.  Is it likely that we saw not just one but possibly five or six.  Our post code is LN8 5LH map ref N53.29360 W0.19169