A mate who used to work for Sainsbury's IT says that's why they start selling Christmas stuff at about the end of August, and Easter stuff immediately after Christmas. It's not because they expect to sell anything much that early, but so they can put up "sale" offers during the main Christmas/Easter shopping period.
Planet X's Voyager Hyper prices were best - up and down like a yo-yo, anything from £7.99 to £29.99, depending on what the random number generator had come up with that week.
Halfords do the same.
When I was buying my previous bike, in 2016 - a Boardman hybrid, I watched the price for a while, and it would be at full price (£500) for a week or two, then another couple of weeks at "20%" off (£400), then a week or two back at full price, and then maybe a week at "25% off" (the offers would often be on "all hybrid bikes" or "all Boardman bikes" or similar, not just that specific one).
I got it during one of the 25% off weeks, for £375. And TBH, comparing with what else was around, it would have been pretty good value even at £500, given it had hydraulic disc brakes and Sram X5 drivetrain (equivalent of Tiagra at the time).