I am in the process of doing a research that aims to measure the grammatical competence of EFL learners and trying to explore the relationship between learners' grammatical competence and grammatical errors appear in their written production.
Pienemann (2007) is a good reference but I guess this has become "old" for your purpose as some advances have been made in the field.
On a different note, I believe that in language learning it is hard to determine what test, questionnaire or whatever may be 100% right and what may be not. Language is an in fieri process, and so is language learning.
My suggestion would be to arrange a test independently and to tailor it to your specific research requirements. I think it would be more appropriate and more original, which is very important for a PhD dissertation after all.
Pienemann processability theory (2007) and Clahsen (1998) show stages of grammatical development to begin with. Then, you can observe the grammatical structures through one form of language production such as oral presentations, or essays. Quantitatively then you can observe correct and erroneous structures. Crafting a test is a good idea after all the reliability and validity work :)
Start by reviewing Pienemann processability theory (2007) and Clahsen (1998). It is methodologically safe to have a procedure of your own rather than reduplicating.
I think that the best resources you need to consult will be official English language tests, such as IELTS and TOEFL "computer-based (CBT) version". There's a good section that tests grammar in a standardised way! Good luck
Maybe you could have a look on the bibliography in AND the content of James Purpura´s (2004) Assessing grammar. Cambridge University Press, and Purpura, J. (2014). Cognition and language assessment. In A. J. Kunnan (Ed.), Companion to Language Assessment. Oxford, UK: Wiley-Blackwell, s. 1452-1476. You might find interesting topics for your research.