For the want of trying, I don't seem to be able to account for NRE (tooling etc) costs so that they are displayed within the 'Project Costs' report.


Am I missing something, is there a field for this or do I have to continue entering it as a task and allocate a fictional resource at cost?

I don't see a "Project Costs" report -- is this a custom report? I see the following Visual Reports:
Baseline Cost report
Cash Flow report
Resource Cost reports

The baseline cost report relies upon assignments as does the Resource cost report. However, the Cash Flow report can use Fixed costs against tasks without assignments.

So, have you used Fixed Costs against tasks?