I agree the charge could cover a range from dismembering a body to disposing of evidence such as a phone.
However, the particular charge was
The charge in full said: "Between 22 February and 3 March in the city of Bristol, without lawful authority or reasonable excuse, did an act, namely assist in the disposal and concealment of the body parts of Rebecca Watts, with the intent to impede the apprehension or prosecution of Nathan Matthews who had committed the offence of murder, knowing or believing him to be guilty of the offence, or for another offence which carries a term of imprisonment of five years or more." From here
http://www.mirror.co.uk/news/uk-news/becky-watts-four-court-charged-5286600
So in this particular case, I don't think this does refer to something like disposing of a laptop, this is about Becky's body as I see it.