but only by using you instruments can you confirm this
Key phrase. If the instruments are simply referenced from time to time to confirm the picture that you are seeing outside, then you are not flying "by sole reference to instruments".
It is easy to miss the point with a discussion like this. Nobody is going to police you on this, so you log what your conscience tells you having read the rules.
Then, when you turn up for your instrument rating course with 150 hours "instrument time" logged, it hopefully won't be a suprise to you if you are not as good as the hours suggest...
2D