Flat narratives and narrative arcs

At tend of Part 1 of Jane Gardam's Old Filth we get the first info about what was so terrible about the foster family that raised Filth, aka Edward Feathers, and his two cousins, Claire and Babs, in Wales when they were young children - on his visit to Claire, from whom he's been estranged for many years, he wakes in the bed in the guest room and has a moment of panic, flashing back to his childhood, wondering if he's wet the bed and expecting to be beaten and humiliated - but he gradually wakes and sees that it's Claire who's entered the room, bringing him tea. Gardam does a good job putting us directly within the mind of a character - narrating the moments of the novel as he/Filth sees and experiences them - though we are in third-person mode it's a third-person of intense individual consciousness, a device pioneered by the modernists - now considered almost a cliche and often misused - too easy to drown in the stream of consciousness - but Gardam uses the method judiciously, to illuminate only key moments that would not be accessible to a distant third person or to any of the other characters. In the final chapter of this section Gardam introduces two new characters - surprisingly late in a novel to do so, especially as at least one other seemingly major character, Filth's Hong Kong antagonist and rival, has been left aside for many chapters. The new characters are Claire's son and his wife, Vanessa, a lawyer like F. - they are part of the British Yuppie set, wealthy, childless (not married actually), in an up and coming area (F. thinks of it still as a slum, he's out of touch with contemporary London) - Claire hopes F. will leave them some money, and we wonder about her motives for getting F. to meet her son. I thought part one, though, would end with more of a kicker - a big reveal of a significant plot development; it doesn't. Although Gardam is doing an excellent job constructing her novel scene by scene out of time sequence, I think at some point it needs to develop one of the conflicts that G. has introduced - we're moving along rapidly, but on a flat plane of narrative rather then along an arc.