As somebody who actually lives in pinko communist Scotland, these are my thoughts:
Not true. The UK has very specific laws about when strike action is allowed. If workers strike without fulfilling those requirements, they can be fired.
Actually, the expertise, work ethic, and attitude of the retail personnel are probably the biggest determinant of profits at a given store.
In the UK if a strike ballot is called by a union, and the vote passes certain criteria (independently scrutinised postal ballot; specific wording of action to be taken; >50% of returned ballots voting yes; and in some instances a threshold return rate), the workers are protected from retaliatory action if they strike. What you suggest would be illegal, and for good reason.
Yes.
Just one anecdote about Apple Store staff (in Northern Virginia in the US) from many years ago: When my father passed away we wanted to play a digital slide show of his life synchronised with his favourite music. We had only a day to put this together and the funeral home in which the memorial was held required a weird file format (and CD format) that I hadn't heard of before. We went to the Microsoft store in the local mall, but when I asked about the format the staff looked at me like I was a martian and they were utterly clueless. Exasperated, we went to the Apple Store. The staff there spent 30 minutes with us patiently mapping out how we could do this, including showing us each stage in the process on a computer in the store, and making sure we understood. They directed us to other stores in the mall for anything that we needed that wasn't sold in the Apple Store. The memorial service went of without a hitch as a result. IMO Apple store staff are worth their weight in gold, and all my US side of the family bought Apple computers, printers and phones for the next decade as a result of the help we got. So that 30 minutes of consideration and expertise from Apple Store employees translated into thousands of dollars of profit for Apple. That's productivity. Productive workers should get paid well.