Hi,
There is an entire thread on this here SonoreUPnP Bridge (beta)
and rooUPnP: Finally a Roon Extension for UPnP Streamers
Also covered extensively in the Naim Community Forum, as there a number of options - see Cheap way to enable Roon streamig to older NAIM streamers - #35 by simon.pepper - Streaming Audio - Naim Audio - Community