There's the common vague feeling that this is a 'Roman' fort (it is true that a Roman site is nearby). Maybe the excavations will highlight that the occasional thing did happen before the Romans turned up in this country.
A couple of years back a cursus was discovered and partially excavated very close by. You'd have been able to see it from up here on the hill. This webpage seems a bit confused and calls it an oval shape, but I'm sure that can't be right? Apparently it runs for at least 750m (east from the sewage works!) pretty impressive.
It does make you wonder whether the cursus was positioned in relation to the Ivel river, and also this hill (this part of Bedfordshire otherwise being quite flat).
I wonder if all traces of it would have gone by the time the forts were built?