I am afraid 'reading body signals' is about as weak a defence as I could possibly imagine. I have been with my DW for 30 years and of course non verbal signals between us are very much a part of all aspects of our relationship but that is something that has built up over decades and something that I would struggle to write down let alone express under cross examination while being harassed by a barrister. They would sound so weak in the face of the "Did you ask her and did you get a definite 'yes' response" question. That is what a barrister would ask and keep on badgering a defendant over and ask again and again. I just don't think it would be possible to rely on 'non verbal' signals as a substitute defence with this new guidance in a court of law.
People on this thread do not seem to realise that the law does not work in a nuanced way. This 'guidance' will have some positive effect in rape cases where there was no real capacity for consent by the woman so the 'well she didn't say no so I carried on' defence will rightly fail.
As I repeatedly said, the issue is in those cases where there is neither a verbalised 'yes' or a verbalised 'no'. Was she enthusiastic is just a qualitative judgement impossible to prove and very much in the eye of the beholder. I think this guidance will not help and could harm women if we start off down the road of relying on 'non-verbal' signals open to interpretation - at worse it opens up the 'well she came to my flat and took her clothes off and she didn't say no' as a legitimate defence.
I do think a lot of the law on rape needs sorting out but this is a massive missed opportunity.