The back wall 39 is between the side walls and is generally at right angles to {HEAD ~ each} of {TAIL ~ the side walls} 47, 38 
of
The back wall 39 is between the side walls and is generally at right angles to { HEAD ~ each } of { TAIL ~ the side walls } 47 , 38
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH