1) Not utilising Long Exposure Noise Reduction
When taking photographs of the stars or Milky Way it is important to keep the length of exposure short to avoid blur caused by movement of the stars during exposure. (It is useful to refer to the 500 rule to help calculate this for your lens - See Below)
It becomes necessary to use a high ISO even when using fast glass. I did not think to enable the 'Long Exposure Noise Reduction' feature on the X-T2 which would have helped reduce digital noise in the final image.
When using Long Exposure Noise Reduction it is necessary to expose for 20 seconds and then wait a further 20 seconds for the camera to complete the Noise Reduction Frame.. but this is not to inconvenient.
To achieve points of light you can use a simple rule that's often called the “500 Rule”. For example; let's say you're taking a shot with a 16mm lens on a full frame camera. 500 / 16 = 31.25 seconds, which you can round to 30 seconds.I was using a 16mm Lens on a Fuji X-T2. Taking into account the 1.5 crop factor of the APS-C sized sensor - This gives a guideline exposure of 21 seconds - 500 / (16 * 1.5 Crop Factor)
2) Not waiting until full dark
I visited Broad Haven around 11:30pm and stayed until around mid-night. I was on vacation with my wife and didn't want to let this diversion impact on the next days activities but it would have been better to shoot later in the evening when the light from the day had faded further.
You should reference apps such as PhotoPills to calculate the darkest point of the night.