Can anyone please advise as to how they best apply the working time regulations for night shift workers.

We have several night shift operatives that are basically here to earn as much as they can while the work is available and wish to work for more than the WTD average 8 hours.

I have looked at the information on the GOV.UK website and other sources, but they still leave me with a few questions:
 

It appears odd that retail is given as an exemption example when experiencing busy peak periods, but no mention is made of manufacturing, which experiences its own peak periods as orders must be met within a timeline. We experience "busy peak times" as the production for orders has to be met. Does this allow the WTD restrictions to be lifted?
 

Occasional overtime – could this be a block of hours eg; worked over two months, if referenced over a workforce agreed 52 week period ?

Taken from GOV.UK –
Limits on night work also don’t apply:
"if a collective or workforce agreement excludes or changes the restriction on night work".

What does this mean in practice – what changes can be allowed?

Many thanks for all replies.