I came across this news article about a referendum to move the island of Jersey from Greenwich Mean Time to Central European Time, and it says that
Some organizations within Jersey’s finance industry, which the island depends on, already complained that a time zone change to CET could disrupt business trading hours with offices in London. These organizations spoke out about the inconvenience such a change could case to their daily schedules, where they would operate on different lunch hours and working times to those of their counterparts in London.
Which seems like a feeble excuse to me.
If they're worried about different lunch hours and working times, why not simply say that in companies A, B, and C (which have close ties to companies in England), work hours shall be from 10 to 6 rather than from 9 to 5, and the lunch hour shall be from 1:30 till 2:30 rather than 12:30 till 1:30 (or whatever)—then they can still be synchronised with their London offices! Just because their clock shows a different number from the one in the London office doesn't mean that they can't keep the same time.