In message , Dave Plowman writes
Look at the drawings in the OSG, regs et al. The bonding isn't all one piece of wire round everything. There's a loop shower cpc - shower feed pipe - hot - cold - bath waste. Another shaver point - sink hot - sink cold - sink waste. Another radiant fire cpc - hot Another cold - one side of radiator.
If, e.g, there was no shaver point & plastic waste to the sink, then I don't believe there is a requirement for any bonding at the sink. Hot & cold are link together by the bath loop, job done.