Don't tell Kirkie, but Robert the Bruce was actually a Frenchman.
I'm not sure we have any "hallowed" ground in the UK. There have been so many battles and wars over the centuries over the centuries anyway.
I don't even think that Agincourt (another war between French nobles!), Blenheim or Waterloo are examples, because neither were pivotal to who we are today.
Some naval engagements might be - Trafalgar for example, or the Battle of the Atlantic, as may be the skies over England in the Battle of Britain, but even there I don't think anything qualifies as "hallowed" in the same way that I can see it for the US in some of the examples given above.
It's a funny thing, but we've never gone in for major memorials for those pivotal moments in history. Bosworth and Naseby remain empty fields, and there's just a small memorial outside Dover for the Battle of Britain. Even the key people don't have too much to celbrate them. Visitors are often shocked that Churchill's grave is just a small plot in the family home with an ordinary headstone, nothing more.
I think Kirkie is right about Bannockburn for the Scots though. Battlefields that are all about the identity of a nation are what we are looking for, and for Scotland that is the one (possibly because it's one of very few that they actually won
) but I don't think there is an English, or even a British equivalent.
She's as nervous as a very small nun at a penguin shoot.