'A' Level Social Economic History time...
Upland areas were more enclosed areas, long before the 17th century, usually on the valley bottoms to stop free range grazing beasts getting into crops.
Especially South Shropshire and the Lake district, there has been evidence of Vikings building dry stone walls in Cumbria.
There is a trick of every 100 yards of hedgerow, each variety of tree/bush is a 100 years of growth.

We had a really interesting talks at the Society of Ancients (SoA) conference a month back, about a couple of Wars of the Roses battles - Edgecote and Bosworth - and the evidence being thrown up by the largest archaeological project in the UK at present - the HS2 rail line. The proposed rail-line route passes close enough to both battlefields to warrant extensive and wide ranging archaeology as neither battlefield has ever been sited accurately, until now.

What was really clear was the impact that ridge and furrow strip agriculture must have had on battles.
Over centuries the fields were ploughed in pretty much the same direction creating substantial ridges (& furrows) - see these modern images of old abandoned ridge & furrow in the landscape of Gloucestershire: https://www.geograph.org.uk/photo/640050

Fighting along the ridges might have been ok, but across them would have been a nightmare - and this might have determined the deployment of armies and the outcomes of battles.
I am not sure whether by the ECW these ridges & furrows had been ploughed out, but my guess is maybe not.

The other item effecting battles is the crops being grown. Right up to the C18th in the UK anyway one of the core crops was peas and beans - a staple that was part of crop rotation and also ideal protien to be dried for winter use. However, it was grown on twigs or sticks, so a pea field might well have looked like a massive abatis or Sudanese zhariba!

NB: I have started to use brown tight-weave sizel floor tiles to represent fields in my 15mm games - as they do give the impression of the ridged fields.
I do also wonder if it was a ridged & furrowed battle-field at Agincourt that also gave the English army an additional advantage?

Food for thought

Mark

Battle of the Beanfield?
https://en.m.wikipedia.org/wiki/Battle_of_the_Beanfield