Thankyou to all of the replies to my question.   I think that balancing them all up I will see if my local Salvos and Lifeline Book fair etc are interested in them and failing that will dump them at the tip.    I live in a home where my wife and grown up daughter are subscribed to multiple streaming services and they find it amusing when I insist on playing my old box sets when the same programs are available to be streamed.

Probably the only reason that I can see to hold onto some of my collection is for some titles like my box set of Fawlty Towers which had one episode that was accused of being racist and some streaming services were threatening to make it unavailable.    

My next challenge will be what to do with several thousand books, mainly non-fiction that are also cluttering up my garage.    I suspect that it might make sense to sell those because not everybody has made the move from printed books to Kindle and not having moving parts, there is probably less risk of having to deal with complaints about them not working and processing returns, which would be a risk with DVDs.