I don't think this changes anything. The laws are quite clear cut on dealing with this issue in particular, I think the issue they are trying to address by releasing this document is the application of the law and how frontline officers and call takers should deal with such a situation.
A few cases have shown that the law was implied incorrectly. The problem lies with each officers interpretation of the law for example, my interpretation of Section 5 POA might be different to my colleague, he/she may arrest for the offence but I may not.
BN clearly have intentions for the best speaking to the COP but I seriously doubt that it will have any major impact on how an officer deals with this sort of situation. It's a step in the right direction but it will fall on deaf ears. I think if you want to be a naturist in the UK you have to use a bit common sense in order to not fall foul of the law.