For anyone trying to ‘reconstruct’ this monument, a recent visit with Stukeley and Ashbee’s words in my head cleared it up.
Stand to the east, looking back over the stones and along the access path. The closest stones [the mouth of the chamber] were all pushed over to the north, ie, to the right. The capstones lay tangled between the uprights on either side. The rear of what Stukely described as a semi-circular chamber was pushed in and to the right, and with his plan in my hand it made sense at last. Just don’t expect to see two lines of parallel stones!
Unfortunately, although still graffiti-free, some digging had been done to the north, around a 2’ hole, mostly, from what I could see, the remains of the roots from the tree that stood in that spot, wedged between three stones. Thankfully there was enough spoil left so filling it in wasn’t too difficult, though it did look hand-dug....two fresh smaller sarsen chunks down there tho, was tempted, just for a second, to have a poke around, but managed to reign in my curiosity, and reported it to Maidstone Museum instead.