What happens in Salvage?

I recorded Salvage when it was on BBC1 in November. I was watching the film this evening but realised that great chunks of it were missing due to a break in transmission during recording. It's a shame as what I saw of it I really enjoyed!

The biggest chunk missing was approximately 30 minutes from near the beginning, from when the daughter discovers her mum with her lover to the lover killing the neighbour. I'd be grateful if anyone could provide me with a synopsis of what happens in this missing 1/2 hour & an overall synopsis of the film!