Brit expat, If you are not following the fundamentals of Islam, you can be muslim in front of the general public, but not in front of Almighty. He provided the rules to follow without any change, not to change or choose according to your likeness or your benefit. According to islamic teaching, it has given you dress code and you are not following it and follows the dress code of non believers, that is it. You are then not a muslim. You are ordered to perform 5 times prayer a day and you choose not to do it then you are not a muslim. You have to fast in ramadan and you don't follow it, then you are not a muslim.
Brit expat, If you are not following the fundamentals of Islam, you can be muslim in front of the general public, but not in front of Almighty. He provided the rules to follow without any change, not to change or choose according to your likeness or your benefit. According to islamic teaching, it has given you dress code and you are not following it and follows the dress code of non believers, that is it. You are then not a muslim. You are ordered to perform 5 times prayer a day and you choose not to do it then you are not a muslim. You have to fast in ramadan and you don't follow it, then you are not a muslim.