You have opened a bag of worms here...
Firstly is the VLA in the Microloght or SEP category?
Secondly,where does the POH say the PIC must sit?
Thirdly what did your friend log?
If the insurance required your friend to be in the LHS then it would indicate that you were not insured to be PIC which means if you logged the flights as PIC regardless of whether you were sole manipulator of the controls you did so illegally. The reverse of this, as an examiner I do whol flights as PIC without touching the controls.
The only way you can log the time is if you were legally entitled to be commander of the aircraft which includes being properly covered by the Insurance.