Found it hard to believe any of it. What teacher calls a pupil the C word? New Zealand seems to have a very different way of schooling!
Penny's character? She behaves in such a random, cavalier way that I couldn't empathise with her at all. Taking her grandchild, an affair with her friend's husband and by the way, why would he take such a huge risk, considering the circumstances? His wife's friend, his colleague and Penny is not exactly irresistible the way she presents herself!
As someone else said, why has 'Tom' box never been looked at in 5 years or why hadn't he taken it when he moved out? Also why did she not see what was going on under her own roof with Phil and Tom? Quick enough to jump to conclusions when she saw him with Ollie.
Very drawn out and then a very quick ending that was not entirely understandable. What took Tom so long to take action?
None of it was plausible, plot holes as many as in the fish net she cuts up!