I'd suggest the size of the workforce is to a certain extent irrelevent - in so much as if it was an workforce or a number of individuals the sheer number of people involved does not necesarily indicate that it was a managed workforce - this is an assumption based largely on modern ideas of trade and commerce. For example, if these axes were the equivalent of million pound sports cars, where and what was the reciprical trade? It could not have been food since a single axe would have provided a years supply of food. I'm very dubious about it being flint, since this is available closer to Cumbria than the east yorkshire coast so what was being traded?

Coming back to the size of the workforce there is another problem - the numbers we are talking about is starting to make up a significant proportion of the population estimates for the country (though I know how variable these can be) the last estimate I saw was for EBA and it worked out at 340k peeps in the UK - I'd suggest based on this the pop of Cumbria could not have been more than 25k - this throws questions over the manpower estimates at the axe factories does it not? So, how did they calculate the manpower? Is this based on full axe production or just blanks.