Welcome to Prestune?

The Welcome to Preston signage seemed a good place to begin looking into travel information, past and present.

As Preston is the Administrative Centre of Lancashire, looking at one of the first administrative records of Preston seemed the most fitting start to research past descriptions of Preston - therefore I looked to Domesday Book entry. 

It's clear that Preston has had several different aliases over time: Priest's Tun (etymology), St Petersburg (Marx), Coketown (Dickens) etc. However Preston's entry in the Domesday Book was the most interesting to me, in that the desciption of Preston was 'Prestune'. 

The calligraphic exert from the Domesday Book writes Preston as 'Prestune' in black, with a red ink line across it (similar to a strikethrough). As yet I am unsure what the significance of this red ink line is (presumably a title highlight? - to be looked into). Looking at this description through present eyes, it strangely looked like an exhibited mistake. 

Furthermore the Domesday book describes Preston (Prestune) as being in Amounderness (Agemundrenessa), in the County of Yorkshire. Given the history of Lancashire and Yorkshire, this seemed quite a controversial find.

I then started to think of the Welcome to Lancashire road signs I had seen which then, in turn, made me return to thinking about the Preston By-pass signs. Were they actually by-passing Prestune? I began to use Kinneir and Calvert's motorway signage template to consider this...