Ask the guys in MAEL Manchester.
Just had a wonderful shift pattern imposed.
I've got this from some disgruntled employees so can't say this is 100% true but:
4 on 4 off in the winter with annualised hours so work 4 x 12 and get paid for 41 hrs.
Then in the summer work whenever they require ie mon night, wed evening and sat day (31 hrs)or whatever they decide at min notice and get paid for 41.
There must be a queue all the way to the FLS hangar dying to get in.
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So that you may not be the martyred slaves of Time,
get drunk, get drunk,
and never pause for rest!
With wine, poetry, or vitrtue,
as you choose!"