Though it was illegal to have slaves, rich people did keep young Africans at home, as servants. WHen they grew up, they were sent to the plantations, as slaves.
Artist: John Giles Eccardt (1720–1779)
 No, Balegule was not a slave. Africans were never slaves in England, ever since 1569, when English court resolved that England had "too pure an air for slaves to breathe in".
This did not prevent English men and women to own slaves elsewhere in the world.
By 1833, when the Slavery Abolition Act made it illegal for English citizens to own other people, some 46,000 English citizens owned about 800,000 slaves.
The Act which freed the slaves also compensated financially the owners, for the loss of their property.
The government paid a total of £20m (40% of the total expenditure for 1834 and the equivalent of £16bn to £17bn of today's money.)
That was money raised by taxes levied on the people, not on the Slave owners.
The freed slaves received nothing, of course.
More than that, in the next 4 years after they have been 'liberated,' they were forced to work for their former masters, unpaid, 45 hours a week.
The staggering sum of £16bn to £17bn is only surpassed by another bailout, that of the British banks, in 2009.