Please be aware that, as a British citizen, you will end up paying for reparations made to your own people! Unless, that is, you intend to pursue payment solely from the descendants of the individuals who were 'compensated'? As matters stand, if the UK government agrees to pay, they will claw the money back by raising taxes, and don't for a moment think that they will make an exception for British people of African descent! They would claim that such an exemption would be 'discriminatory'.
This is a clear case of being careful what you wish for! Or at least being careful in the way you go about getting it!
I'm talking practicalities here, not ethics, BTW.