I'm not so sure you can categorically call it a henge from the 1953 excavations reported by Dyer (Dyer, J 1961 'Waulud's Bank, Leagrave' in Bedfordshire Magazine vol 8 pages 57-64) suggests that the surrounding site would have been marshland and with a bank and ditch on the remaining sides having circa 8ft deep and 20ft wide ditches would be fairly substantial defences for neolithic standards. The bank itself is incomplete design and Dyer points out that the walls are heavily mutilated to ploughing and would have been much higher.
Granted the fact that there is not much evidence of later occupation on the site except for sporadic Iron age finds is percieved as temporal occupation and as Dyer puts it 'squatters,' however again it is difficult to assume this if the earth has been under the plough in previous centuries.
Dyer points out that a community could easily be sustainable and with the abundance of fish and fowl etc. One should use caution when mentioning the word 'henge' and think about what the word means and how it can be incorporated when looking at prehistoric societies which is always going to be tentative.
To me it is a place of habitation and whether the earthworks were of defence or not is reallly insignificant to its primary function. The only posibilities realistically are protection, boundary (ie statement of territory and yes this could include religous possiblities though difficult to prove), or aesthetic show.
Something is not right. This message is just to keep things from messing up down the road