RHG, thanks for the post. I was able to replicate your solution and return a value.
I'll have to read up on the data handling however as I do confess that I have no idea how to pull out the fields for a specific product_no and their respective numbers.
As a side note, from what I can tell there's no way to 'debug' and use any of the JsonManager fields etc to see if a JSON load worked. I couldn't see any data. No big deal, but for others who follow this trail.
Thanks again
Graham