At the moment the So's bike have a Disk on the front (from the spare box) and V's on the rear.
Front is a very old XC4. This brake has been great to me and I never had any problem with it. However she finds it doesn't brake… So I have tried it and I find it work just the way it should be. Is it possible that she can't squeeze the lever enough?

Any pointers???

Even the cheapest Shimano will lock up a wheel with single-finger braking.

yes but she has very tiny delicate hands;)

Is the lever too far away for here to reach easily?

stu nope I checked that too as it was an issue on her first ride.

Juan – my daughter is 13 and has no problem stopping using Deores. Just buy her some decent brakes.

what do you mean decent brakes those are hope 😉 (see what I have done here 😉 )

* sniggers *

i knew you' love it druidh 😉