Hi Ker76,
I don't know if you maybe already solved your problem, but I might have an idea of what's wrong.
You say that your DLNA servers are configured fine, no objections, you might however check something in their configuration:
What is the IP / interface you chose in the configuration? Because your WiFi adapter and your LAN adapter on the laptop have different MAC addresses and most likely are assigned different IPs when connected to the router. In order to make the DLNA servers stream on both IPs, you must either enter both of them in the configuration (if it is allowed), either enter 0.0.0.0, then they will stream on all available interfaces.
I will bring an example for clarity:
WiFi adapter gets the IP 192.168.1.7 assigned, and the LAN adapter gets 192.168.1.8.
If you configured DLNA servers to stream on 192.168.1.8, then this is the only IP it will ever use, so it can never use 192.168.1.7 when you connect it through the WiFi. If you use 0.0.0.0, DLNA servers will stream on both of them.
Hope this helps
P.S.: to my knowledge, PS cannot have any knowledge what are the DLNA servers behind on their end, WiFi or LAN, this is why I think the problem is at the source of the stream.