Hi
@Katinahat - welcome back!
I think that it depends on whether you wish to use all your bags, or whether you are happy to have some which will rarely be used, or maybe even never, but you love them and would miss them if they were gone. Some people wish to only use their bags, whereas other people have a little bit of the collector in them and do not expect their bags to repay their purchase price/cost per wear.
It is wise to let go the ones you definitely do not feel any attachment to, as you are currently doing, and which also no longer suit you. Also, it's great that you have identified ones you'll never let go.
It's interesting that the Seaton is a potential for letting go; as you consider it too formal, perhaps that's the issue also with the Bayswater (original/heritage style) if that's in a sober colour?
Don't let other people's choices influence you too much; you and your lifestyle are completely different to them. If a bag no longer serves a purpose for you, and you wouldn't miss it, let it go to a new home and use the funds to purchase others which you'll use and enjoy.
If, after a year, you've not missed particular bags that's probably a good indicator of what you will do. However, try them on again just to make sure. Replacing a bag, especially one that is older and/or hard to find, can be frustrating as it's often difficult to source them in the condition you'd require.
Let us know how you get on! 😁