Until recently, the essential sources at disposal were Caesar's own accounts, fortunately generally considered reliable, in the Book IV of his commentaries.

Initially, Caesar's fleet sailed to the Cliffs of Dover

As this was performed rather tardily by them, he himself reached Britain with the first squadron of ships, about the fourth hour of the day, and there saw the forces of the enemy drawn up in arms on all the hills. The nature of the place was this: the sea was confined by mountains so close to it that a dart could be thrown from their summit upon the shore. (IV, 23)

The site was, obviously, considered ill-fitting as a landing point and was probably chosen in the first place after Volusenus' scouting and informations gathered from Belgians, having commercial and probably political relation to Southern British peoples and that, according Caesar, salied mostly to the South-Eastern harbours of Britain.

Meeting both with wind and tide favorable at the same time, the signal being given and the anchor weighed, he advanced about seven miles from that place, and stationed his fleet over against an open and level shore

Those descriptions rather well fit eastern Kent beaches between Walmer and the mouth of the River Stour, and several landing points were proposed : Deal and Walmer especially whom distance was roughly the same than accounted for by Caesar from Dover.

Recent archeological evidence of a Roman fort on the Isle of Thanet and Pegwell Bay and fits roughly Caesarian description, altough possibly more on the -54's expedition, could hint at a more northern landing point than previously held in -55, or with more caution, a larger reckoning of beaches by Romans than previously tought.