Best place to advertise audiophile speaker components (UK)

Hi, hoping you can help with this: I have just purchased a pair of speakers from a middle aged lady who is disposing of the estate of her recently deceased husband. He appears to have been either a builder of audiophile speakers or in the process of setting up a business to do so. She has a number of drive units, Mundorf AMT ribbons and Purifi mid range  drivers, and a number of class D amplifier modules all of which are new and boxed. In the brief time I was talking to her I noticed a number of cabinets in various stages of completion, these are of 2 way configuration and what in the UK would be considered to be small bookshelf type speakers. She has some boxes of other components, cables etc. and (I would imagine) some high quality crossover(s) or components. She is experiencing some difficulty in disposing of these components, she has sold most of his equipment, amps and subwoofers etc.  She is located in London (UK) and has no idea where is the best place to advertise or who to contact. At first sight there could be an opportunity for a prospective buyer to start a manufacturing business. She has a lot of it packed up ready for his family to have shipped home to the US, but they have now decided not to undertake this due to the costs involved. As a result she has yet to do a full inventory, but realises that she will need to do so as soon as possible. So does anyone have any suggestions as to the best place(s) for advertising the items?
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Facebook Marketplace, and/or DIY speaker discussion groups on Facebook.  Plenty of a good pictures, and good detailed descriptions always help.

I'd also suggest looking into and contacting any audio societies that may exist near London.