1) The way Europe controls us (and the rest of the countries in the EU) is to issue Directives. Contrary to popular belief, these are not laws, but directives that the individual member countries have to turn into laws within a given timescale. It the UK, the appropriate legislation is the Working Time Regulations 1998 (it has been amended twice since then, once in 2007 to do with annual leave rules and again earlier this year to deal with rules for junior doctors).
2) If the employer and the employee sign an opt-out clause, the employer does not need to abide by the WT Regulations. But only regarding THAT part of overall employment law.
3) I simply don't understand your question. Your example seems to quote 2 shifts, with a gap in between. Is the employee 'on call' during this gap period, then? The WTR limit the maximum number of hours per week to 48, but they can be averaged over a 17 week period. There are also different rules in certain types of industry. The WTR are nothing to do with minimum pay rates. Can you be more specific about what you mean, please.