Boxing Day seems like the UK equivalent of Black Friday for USA inhabitants. Can anyone offer me additional first-hand experience? Is it as fun and/or chaotic as it is here? Are the deals worth enduring the crowds and travel for? Highlight v. Must-avoid? Do the tubes run as normal?

We are currently planning to go to Harrods to start our day, starting as early as possible. This one is non-negotiable, my friend is bent on it, so although I know it's probably a bad choice, it's going to be our first stop if it's open. Fortnam & Mason would be another, and any nearby Christmas Markets are a possibility, as well. I assume they'll all probably be packed all day, but we're mentally ready for that. I shopped in NYC's Macy's and Saks on Black Friday this year, and perhaps it's the times we're living in or the lack of crazy steals, but it was tolerable.

Does anyone know the Hours of Operation for Harrods or F&M on that day, whether posted for based on historical data? Nothing specific to Boxing Day are on their sites at the moment. All other resources (including reddit searches) are very out of date.