This map shows the position of locations containing 'anderida, battle' centered on Battle in Sussex.
This map shows the relative population sizes near Battle/Hastings for villages which were responsible
for Salt production in 1066. The data is derived from the Open Domesday Book (links provided at the bottom of the page).
The black lines show known Roman Roads, the Red ones ancient trackways(Ivan D Margary), with the purple ones showing implied
Roman roads provided by place names.
>= 5 and < 10
>= 10 and < 15
>= 15 and < 20
Salt production in the Hastings area from Domesday Data
Could salt production have been a factor for William landing near to Hastings.
As you can see from the map most of villages that produced salt were either near the Romney Marsh or between the
Pevensey Marshes and the Ouse basin, however salt production was occurring at Ashburnham which is about 10 miles inland today,
and so provides evidence for the idea that the sea reached much further inland in AD1066.
So Invasion to control salt production would be very unlikely.