I found out, with the help of  the members of birdforum, that the dragonflies I photographed on monday were all Common Darters Sympetrum striolatum. From what I understand, the male is the red one and the female is the green one. They certainly are common at Eske and I have seen plenty of them over the last few months. Here are some more photos of them:

I guess it is about time I got a book on dragonflies so I have some idea of what I am looking at, particularly as I am told that Eske and the Leven canal are important areas for dragonflies and damselflies within East Yorkshire.