Gate Fulford had only the troops from Mercia and Northumbria. Stamford bridge was a solid win for the English, therefore Harold's army which returned south and offered battle right away was not severely mauled: not was it particularly tired out from marching, as they were ALL mounted.

This idea that English armies marched around on foot is unsupported with any evidence: while the evidence for horses is very great, from the period artwork, the distances the armies routinely move, and the descriptions of the "Force" getting "horsed" and raiding far and near, yet being tackled by the defenders time and again. Also, specifically English armies are mentioned in the 1066 campaigns as being mounted. The thegnhood were certainly all mounted, and a force of c. 7,000 were mustered from the shires Harold drew from for Stamford bridge. By the time he had come back to London more troops had arrived. Thegns had household troops, just like the earls had household thegns and housecarles; it is not according to the best evidence to assume that these household troops (geneats) were infantry only. At the very least, I think it would be safe to say that each thegn had one mounted follower; but most likely two or more is what thegns had in their contingents. Ergo, the c. 7,000 thegns of Harold's muster would easily produce an army of over 20,000 men. Then you add in the housecarles and any local troops from Kent and Sussex who were mustered at Caldbec hill awaiting the coming of the king and his brothers.

The contention of the ASC and Florence of Worcester that Harold fought before all the army had come (with less than a third of his forces in array - before half the army had come) refers to a very real situation where Harold offered battle before his full muster had arrived. I interpret the "one-third" only in array to mean that the army he had on hand was only a third of that available at that time; i.e. perhaps 10,000 or less actually ready to fight. This accords well with the consensus for a smaller army; and it also allows that perhaps many troops remained back in the edge of the forest and never fought until the battle was nearly over, and the Normans came to them (pursuing the broken English forces which had fought all day out on the ridge); it is very possible that only a third of Harold's entire army had actually taken up positions on Senlac hill; an army of 10,000 or more can effectively hold the hill, but not the entire length of the ridge, and down into the marshy areas to the west.

I have never war-gamed Hastings with more than c. 10,000 to a side. But I would really like to try out a bigger version, with Harold's army along the entire ridge and down in the marshy areas - and of course in possession of the "hillock" out in front of the main ridge.

The battlefield is easily capable of holding upwards of 30,000 troops per side, if you take the fullest extent of the hard ground between the marshy areas to east and west.