I have never experienced this at Waylands, But i have experienced a 'kaboom!' every now and then whilst relaxing on the downs about 3 miles away. It baffled me for ages. I then experienced it at Liddington Castle much more strongly.
It seemed to be the Lorries (the big ones!) on the M4 (close) going over a bridge and the vibration and boom sound that accompanied was felt very strongly.
WF