What two oppressive circumstances did Sadler find children working under within British factories?

I assume this question is referring to the “Report of the Select Committee on Factory Children's Labour," more commonly known as the Sadler Report. The report was written by a member of Parliament, Michael Sadler, who chaired the Select Committee and led its investigations into the working conditions of child laborers in British textile factories.
The Committee had been appointed because of an ongoing debate in Parliament about whether the government should regulate child labor. Sadler had previously tried to introduce a bill which would impose limits on the ages of children who could be employed and the weekly hours children could be made to work. Parliament rejected the bill and requested more evidence before Sadler’s proposed limits could be considered.
Sadler spent about a year between 1832 and 1833 gathering the requested evidence. His Committee interviewed 89 witnesses, many of them former child labourers, as well adult factory workers, a number of physicians, and some factory owners. The resulting report detailed the appalling working conditions children were subjected to in the textile factories, among them:
Long hours: the children worked, on average, between fourteen and sixteen hours a day, with a single one hour break around midday for lunch. The work was physically exhausting and the machines were very dangerous, so the long hours the children were forced to work contributed to the high rate of accidents in the factories. Peter Smart, another former child laborer, testified that the children had “[p]erhaps not above four or five hours in their beds” per night.
Physical abuse: the children were frequently and severely beaten by the overseers in the factories, sometimes as punishment for tardiness or mistakes, but often simply to keep the children awake. Former laborer Matthew Crabtree, who began working in a factory when he was eight years old, testified to the Committee:

[The workers] must keep with the machine, and therefore however humane the [overseer] may be, as he must keep up with the machine or be found fault with, he spurs the children to keep up also by various means but that which he commonly resorts to is to strap them when they become drowsy . . . the dread of being beaten if we could not keep up with our work was a sufficient impulse to keep us to it if we could.

The children working under these conditions were paid very little. The physicians who testified to the Committee stated that the demanding, repetitive nature of the work often warped the children’s physical development; they were stunted, with bent backs and bowed legs.
The report’s findings caused a media furor in Britain, as people were confronted with the spectre of what was, effectively, child slavery in their midst. Later that same year, in 1833, Parliament passed the 1833 Factories Act for improving children’s working conditions. The Act forbade the employment of children under nine years of age and limited their maximum working hours to twelve per day.
https://history.hanover.edu/courses/excerpts/111sad.html