A pack of fairy tales, exaggerations, and downright falsehoods. That such a well know publisher should put their name to this book is shocking.
For example: 'Beachy Head Woman' was born in the Eastbourne area of Britain, and her ancestry was Southern European, most likely from Cyprus. She was not Sub-Saharan Africa - DNA analysis is quite categorical on this.
Hadrian's wall was built between AD 122 and AD 128 by three legions (II Augusta, VI Victrix and XX Valeria Victrix). None were black. Over a 100 years later a there is evidence of a 500-strong unit of Moors manning one of the forts near Carlisle. They were from Mauretania (in the present day North African coast - not to be confused with present day Mauritania). The Moors were Berbers and therefore as white as any Roman. Indeed the Egyptians universally painted them as white.
John Edmonstone did not work for the museum, he gave lessons on taxidermy to students at Edinburg University. I'm not sure taxidermy has 'shaped British history' as claimed or or that he played any significant role in the theory of evolution.
Iris de Freitas Brazao was from British Guiana. She spent a few years in Wales studying at Aberystwyth University then went home. She wasn't Welsh and had no impact at all on British or Welsh Society.