The only real way we will ever be afford to get a complete picture what avebury looked like would be if you could write a feature film and get them to pay for the models and computer generated reconstructions. id go with the arthur merlin saga. The main criticism of the Athurarian saga has always been that it is set in a norman/medieval setting as everyone knows there were no castles until norman times. Well this is blantantly not true as Silbury had a tower on it in saxon times and probably earlier, and marden had ramparts, and a mound and tower perhaps. So if you make a leap of faith as say Stonehenge is the roundtable of myth, and marden is camelot and Avebury is the great nemeton and Merlin the archdruid. They found " the slaughter stones" near Avebury flat stones marking mass graves, the skeletons hacked about. if there was a battle maybe during the 2nd roman invasion then we have the roman taking avebury, burning stonehenge and sacking marden. Arthur injured in the last battle(Liddington) as the kingdom falls, and fleeing first to bath with the romans on their heals. The romans take bath and the druids flee west to bristol and take ship to angelsea, whist arthur sails for avalon to get healing. then you have the roman invasion of angelsea and bouddican revolution, the rumour is arthur lives and will lead then in the final battle against the romans, but arthur is dead and the day is lost. Get the guy who directed Lord of the Rings to be the director and were sorted. Anyway if wishes were tenners id be rich.