Not, do gather that she's currently in KS2?
If so, then the 'plugging gaps' thing is MUCH easier. As she is in a class who remain together, with no more than a couple of teachers, times for intervention can fairly easily be 'squeezed' out of each day - assemblies, registration time, maybe the last 20 minutes of Art, or instead of changing time for Games [given time to change at break or lunch], for example. While it has to be balanced carefully for the child, it is fairly straightforward in a timetabling sense to squeeze about 30-40 minutes, in 3 short blocks, in each day
In secondary, it is harder because there is less 'unstructured time so it is difficult to remove from a lesson without her falling behind. A school I am aware of sets aside a subject block [usually used for a second language in Y8] for additional 'core subject' interventions, and then has a couple of GCSE option blocks that are used for intervention rather than the child doing an additional subject - so they will end up with 8 GCSEs not 10. Another possibility might be the very beginning of the day, possibly arriving 15 minutes early, or at the end of the day, or a lunchtime session [SEN rooms are often open at lunchtime], or taking up a registration session.
In terms of attitude to challenge, possibilities might straightforwardly include counselling. It might be targeted TA support in those specific lessons where challenge is highest. it might be small 'nurture grup' type events where 'non academic but fun' challenges can be part of every session, so that the child can try and fail in a supported group in a way that 'doesn't matter'.