Good morning Stuart,
Thanks for getting in touch, by definition our demographic age range is slightly higher for Just You than it is for Travelsphere, however this is not an exact science and I would, from experience, put them at nearly identical. We have also seen an increase in younger travellers across both brands, my theory for this is that Just You and Travelsphere are safe ways to explore to world.
I'm sure there are members on here who have travelled with Travelsphere before who could offer more insight,
I hope this helps,
Kindest,
Ben