Wessex Woman, perhaps I wasn't clear. I was a bit rushed and pre-occupied as I was typing my post. I wasn't saying that the hunter gatherers couldn't count, I was saying that they didn't and didn't have number systems to represent numbers. Also, this is still up in the air. Some linguists have taken issue with the chap who has studied the Piraha, and languages which previously had been described as only having numbers up to three are being looked at again. Ability to learn to count does not necessarily mean that one does count. I recently taught a student in his 40s who had learnt to read over the two years prior to taking my course.
As interesting and compelling as animals counting and doing addition and subtraction is, (and it is fascinating, as is research around chimps and parrots learning language) I think there is far better evidence that people from hunter gatherer societies can count, and that is that people from other societies can count, and the fact that many people who've been assimilated from hunter gatherer societies into other societies use number systems. In fact, unless I'm mistaken, I believe there are languages that take their number systems from colonial languages: Portuguese, Spanish, English.
Technically, this discussion is off topic but I raised it because I believe it makes some important points pertinent to the discussion of whether proto-literate English had a written number system.
All people can read and write, whether that be pictographs, ideographs, syllaberies or alphabets, or a mixture of two or more of them. It's just that for most of human existence, no one did. Whether people write or not and, in this case, whether people have a written number system is a question answered by whether or not these things have a utility. Did the proto literate English need to visually represent numbers? A bit of wandering around the net has dug up a source
that says that the Norse writing in runes mainly represented numbers by either writing out the whole word, or by representing it by the first letter of the number word, which is similar to what the ancient Greeks did. I would imagine that the proto literate AS did similar, but I cannot find anything that supports this guess. A further guess is that I would imagine if there was a native written number system, we'd know about it. The New Age people would have been all over that stuff.