Thank you brilliant.Would normally say go for a gold plated adaptor, but your plugs aren't gold so this is all you really need:
You might prefer this type of alternative, though it could put a bit more strain on the Bose socket:Twin RCA Phono Sockets to Mini 3.5mm Stereo Jack. Twin 2 x RCA Phono Female Sockets to Mini 3.5mm Stereo Jack Plug.www.ebay.co.uk
Have you ever actually known anyone that's been confused by the term 'phono preamp'?It's often called a "phono stage" to avoid confusion.
There's quite a good explanation on https://www.cambridgeaudio.com/usa/en/blog/phono-stages