Hmm, the claim seems a bit far fetched. It's a pity SU1142 and SU1143 are absent from the gov lidar library. The lie of the land is weakly uphill from the proposed moat only in a directly westerly direction and lidar fails us 200 metres from the henge in that direction. Contours reveal no evidence of a depression that a stream would have created (anyway, people have looked for that before). A leet or stream from the north-west or the the north would have to cross a bit of a valley some 5 metres (at least) lower that the proposed moat so one would expect to see some evidence of the construction, even today.