I am struggling a bit with this one: https://en.wikipedia.org/wiki/Grave_field

We do have 4 for this connection (Halstatt, Sammalahdenmaki, Hedeby, Southern öland), but is it distinctive enough to set it apart from 'regular' cemeteries? Grave field is defined by wiki as "prehistoric cemetery".

We also already have tumuli, a very specific kind of grave field.

Any ideas?

Grave field are cemeteries with no above ground structures (such as gravestones). Maybe we separate cemeteries with gravestones from grave fields.
Tumuli have a mound above them, they are a type of a cemetery, but different from grave fields.

But not quite what the Wiki "definition" of "Grave Fields" describes - https://en.wikipedia.org/wiki/Grave_field
It actually defines a tumulus field as being a "type" of "Grave Field" based on burial custom.
It also lists Sammallahdenmäki as being a "Grave Field" despite the piles of "above ground" stones there! (I have checked the Nom File and the phrase isn't used)

The phrase seems to have particular (but not uniquely) Nordic/Bronze age application. I note that there is a Swedish word ""Gravfält" and I wonder if its use is "specific". eg. On Oland "Gettlinge Gravfält. Grave field at Gettlinge. Gettlinge Gravfält is one of the largest and certainly most beautiful prehistoric burial sites on the island of Öland"

We were in Tamgaly a couple of years ago and it has an area of bronze age "graves" with little or no above ground signs - but it ALSO has things called "Kurgans". Its Nomination File. The phrase "Grave Field" isn't used however in the Nomination File ut Wiki includes "Kurgans" as "grave fields"

In wonder if the phrase "Grave Field" is used specifically enough for us to try to categorize examples of areas containing graves as between the other possible words for them - cemeteries ,Tumuli, Necropoleis etc etc

Where my hesitance lies is with the specific Bronze Age or prehistoric connotation. Are all cemeteries from that period grave fields? If that's the case, I would not like to have it as a separate connection as they already are distinguished by their time line (and even more so when the definition is not limited in time but also in region as well, as may be the case here too).

On the other hand, it could be that a grave field has characteristics in lay-out/shape/use/whatever that differ from cemeteries. In that case I would support a separate connection. But the wiki description does not support that.