You are not a lawyer I think so there is no requirement for you to interpret or even have ever read the ANO or any other legal text. (Even if some like to debate it
)
You are a pilot I think so you must be familiar with the AIP for your country and the other countries you fly to especially the GEN part which gives you all the rules and differences that may exist from the international standards (ICAO) which you will have been taught during your training (if it was done as per JAR-FCL).
Simply put you are required to comply with the most restrictive version of any requirement when abroad.
With regard to the medical question please check the uk AICs (pink I think) where there is further guidance.
regards,
DFC