Can I optimise the wireless network settings to prioritise the data to the wireless music player?
Sorry, but no. There is no option for your AirPort Express to do so.
Is the Express the only router in your network configuration? Which exact model is it? What is the make & model of the Internet modem that you have the Express directly connected to by Ethernet?
Where is the wireless music player located in relation to the Express when it experiences audio drop outs?
Virgin Media Super hub internet modem/router is the start point
Hard wired to Apple Express
Not sure which one is the wireless music player
Connection decribed as fair to excellant when cursor is hung over each client
It is about 10 meters away from the Express down a hall into the kitchen, no doors/walls but no direct line of sight
Placement of the AirPort Express relative to your Virgin Media Super hub is not critical since it is connected to the hub by Ethernet; however, the placement of the Express relative to your Minx could be a factor.
You will want the Minx to be within a 25+ dB SNR range of the Express. Please check out the following AirPort User Tip for details. Although the article is discussing the placement of an extending base station in an extended Wi-Fi network the means to measure the Signal-to-Noise Ratio (SNR) still applies.