Victorian Coinage 2023 Legal Tender

Britain has never demonetized its post-1820 predecimal coinage; they are all (theoretically) still exchangeable a the conversion rates established back in 1970. You can, in theory, go down to the Bank of England and give them 20 shillings, and they'll give you a 1 pound coin.

However, they are no longer "legal tender" - in the sense that you can compel someone to accept them in payment for a debt. You'd be a fool to do so anyway, since all predecimal coins contain more than their face value in scrap metal, not to mention their numismatic value. The legal tender status of predecimal coins was removed in 1990, once the decimal coins were decoupled from their predecimal equivalents in terms of size and weight.

Correct; "legal tender" doesn't mean what some people seem to think it means. It doesn't mean that a shopkeeper is forced to accept it in payment under any and every circumstance. It is applicable only in a limited number of circumstances, surrounding payment of a debt. Regular shopping doesn't incur a debt, since the goods are not transferred prior to your payment; the merchant is freely able to postulate restrictions on the type of money they are prepared to accept, and there's nothing you the customer can do about it, since you haven't purchased anything from them yet.

A debt would be incurred if, for example, you go to one of those restaurants where you're given a bill at the end of the meal, rather than pay up-front for the food. In this case, you've already received your goods; it's way too late to give the food back. Other debts would be tax debts or other bills for services.