Thank you for your replies but you haven't really been able to offer any real reasons.
I know that if I want to fly for the police I will have to get the time, I'm just trying to understand the requirement. I'm well aware of the differences between single and twin emergency procedures and understand that some training would be required, but 500 hours!
In addition to that, at the moment I am very current in low level activities, flying Hughes 500 etc. I would suggest that after spending around a year flying straight and level in an S61 or similar, I would be a less competent pilot in those areas.
Thanks again.