Hi Toyboy,
In this case we'd recommend adjusting your connection and quality setting. This setting can impact how long and how much data is required to stream music on your Apple Watch. You can learn how to do that here:
"Choose cellular connection settings
To listen to music over cellular, you must be using Apple Watch with cellular.
- On your iPhone go to Settings > Music, then turn on Cellular Data.
- Tap Audio Quality, tap Cellular Streaming, then choose a quality.
Note: Higher quality settings consume significantly more data."
Here's a link to the full resource: Do more with Music on Apple Watch - Apple Support
Take care.