^ These answers I've given previously should be pertinent.
Based on comparison of the Bryce Report with the 'Grey Book' released by the Belgian and French governments during the war, at least 40% of the events described in the Bryce Report either are confirmed to have happened, or likely took place. Although the gutter press in the UK, like John Bull, picked up hearsay stories from soldiers and refugees of 'bayonetted babies' and 'nuns rung to death in bell towers,' the atrocities that remained centre stage in Allied propaganda and in the minds of civilians did take place: The Burning of Leuven, the mass shootings at Dinant, Aarschot, Tamines and Liege, and by the Belgian government's own numbers, over 5000 Belgian civilians were murdered in August 1914 alone. John Horne and Alan Kramer put the death toll including French civilians, at c. 6300, in their book German Atrocities 1914. Although the title 'Rape of Belgium' was applied more in the metaphorical sense, there were rapes documented in August 1914, and considering both how recurrent it has been in wars throughout history, and how taboo it was at the time, it's almost certain that more rapes went unaccounted.
The Bryce Report did contain a large amount of hearsay, but to be fair Bryce made sure to state at the beginning of the documents that not all the accounts given might necessarily be truthful. The big issue was that the Franco-Belgian 'Grey Book,' which gives the best account of events, was not published in English until well after the war, and not circulated widely enough. The result is that instead of being supplemented by more reliable, foreign language sources, English-language ones were savaged by writers like Arthur Ponsonby and Harold Lasswell, whose accounts of the effects of propaganda in the Great War accused the British government and press of at best exaggerating, at worst completely fabricating, the Belgian Atrocities.
John Horne and Alan Kramer's book, as well as Rehearsals by Jeff Lipkes, are both excellent accounts of the atrocities and their legacy.