I personally think we are intended to give a satisfactory result where there is an absence of C1's, C2's and FI's. I can't find anything in the regs, forms, guidance etc that backs up the idea that we can give an unsatisfactory result where only C3's are present.
If an unsatisfactory report has only C3's, what remedial work should be done to bring it back to satisfactory?
From the OSG:
Where an unsatisfactory result has been recorded, C1 and/or C2 observations will have been included identifying the reason(s) for the result. Fl (Further Investigation) may also be recorded where the inspection has revealed an apparent deficiency which could not, owing to the extent or limitations of the inspection, be fully identified and further investigation may reveal a code C1 or C2 observation.