What is making me suspicious of SH's involvement is the kidnap story. If NM had planned to kidnap Becky to take her to a wooded area and teach her a lesson, I really can't see how he could have pulled that off with SH and their child at the house. If SH wasn't involved at all, then surely he would have carried out that plan when he was alone. Would you really kidnap someone and have them in the boot of your car, with your girlfriend and child in the car at the same time?
For me, the kidnap story has more of a believability about it if it was a plan to kidnap Becky for sexual purposes by the pair of them - basing this on their texts and the fact that 2 stun guns had been purchased.
Obviously I have only seen what the media has published, so can only theorise based on that - and from putting those pieces together, I think that Becky's death might have been a sexual assault/attack that went wrong, whilst the child was watching CBBC downstairs.
The kidnap story is 'better' from NM's point of view, than admitting to his mum and stepdad that he was trying to rape Becky or assault her.
I don't believe SH's story at all as it makes little sense and has far too many bits of 'luck' in it - she spent exactly the right amount of time in the garden with the child, in the rain, for NM to do what he did. She just happened to fall asleep and miss all the goings on regarding the moving of the body parts. She wasn't at all suspicious that her partner went out buying an excess of cleaning products, cling film and bin bags, and a new saw, at exactly the time his stepsister was missing. She suddenly decided out of the blue to visit her estranged family for the first time in years, just when the police wanted to search their house, and so on. I'm aware that there probably needs to be a lot more hard evidence to give a jury reason to decide without reasonable doubt though. But I'm just explaining why I don't automatically believe she is entirely innocent - but I totally believe that everyone should be assumed innocent in the eyes of the law, until proven guilty.