Can I validate my licence for test/dev site and for the live site?

Yes. For the same project, you can validate the license for one development/test site and the matching live site.

If you have validated your HBook license for a website, but you no longer need it on this website, you can remove the license in HBook > License. This is useful if you need several staging sites or if you ultimately do not use HBook for a website, but wish to use the license for a different project.

A license can be used for 1 end product only. You will need one license for each project you wish to use HBook on.