I never though I would do it, but have decided on my current collection of bags. Thanks everyone for all your help! I am keeping:
Mulberry gold lily (for parties and dressy occasions)
Mulberry OS Alexa in Oak (will store this one away as it is brand new and save her for a Christmas or birthday present for myself)
Mulberry OS Alexa Petticoat (not in photo)
Mulberry Black Alexa (great winter bag I use loads)
Mulberry oak alexa postman's lock (use loads)
Mulberry Darwin Roxanne
Mulberry Oak Bays (for work events)
Balenciaga Gris Poivre Part-time
Alexander Wang Petrol Rockie
Chloe Paddington Capsule (my first designer bag - can't bear to lose her!)
Stella Fallabella
Marc by Marc Jacobs blue summer bag (until she gets worn; then replace for something else light and colourful)
As you can see Mulberry was my first love and only now am I turning to other brands.
I wanted to get down to 10, but 12 isn't bad for a first effort
Thank you all so much again!