The 48 hour working week rule is actually averaged over a rolling 17 week period so it is quite easy to work well over the 48 hours in any given week.
In any case, the Working Time Regs 1998 provides an opt out clause for anyone who doesn't want to be restricted to 48 hours. There are several areas outside aviation which take advantage of this, the security industry for one.
Pilots involved in Commercial Air Transport are limited to 900 hours per annum block time and 2000 hours working time - no opt out permitted - under the Civil Aviation (Working Time) Regs 2004 but pilots involved in aerial work activities are covered under the Working Time (Amendment) Regs 2003 which, like the 98 Regs, provides an opt out.
It seems a bit crazy that engineers have no effective restrictions on their working patterns. As said above, when the wheel comes off and it is proved that fatigue from working back to back shifts was a major cause then maybe someone will sit up and take notice.........although this has already been cited as a causal factor in some instances........slamming stable door after horse has bolted springs to mind!!