For those with change pots that have tonnes in them, the old round pound stops being legal currency from midnight today having been replaced with the new multi side pound coin. Tesco have said they will continue to accept them for 1 more week and some stores might but if you have the old pound coins, ideally today is the day to get ride of them. If you still end up with some then the British legion have said they have an arrangement with the banks, that you can still put the old pound coins into their charity collection tins/pots upto Remembrance Sunday , the 12th of November.
Yes but it varies by bank, here is a article that might be helpful? https://www.theguardian.com/money/2017/oct/14/old-1-pound-coins-where-spend-them