Helena is my favorite of QV's daughters, I can't explain why she just seems like she was genuinely great person. Helena and Christian had a quiet life compared to her siblings, and Helena's marriage was the longest of QV's children. I think she rather resembled her mother, they both have the same round face though, Helena's features are slightly different.
Some Pictures of Helena and Louise as Children
All of QV's Daughters, except Beatrice, I believe Helena is on the far right
With her mother
Helena with her mother and Alfred
A couple more of a young Helena