Does throughput tail off during 5pm-12am at all,? the yellow spiking is known as jitter not good if you are a online gamer or use VoIP type apps
I for one wouldn't be happy with a ping monitor like that, but it does look to be ISP network related as it increases from 4pm onwards till 2am the next day, (peak time ) So it's likely due to the utilisation levels, TT would appear to be running some of their links hot,