Being a bit of a noob, I managed to figure out attaching the camera to a null, the null to the spline, then a vibrate tag to the camera. It worked OK.
Applying the vibrate tag to the spline did nothing. I don’t know how to use a ‘repeat’ function so I gave that a miss.
The Xpresso file that Cactus Dan uploaded looks to work brilliantly. Although, when attached to my spline moves too much and I have no idea how to reduce the height that it bounces because this is the first time I’ve ever noticed Xpresso.
This is what the Xpresso editor looks, can you help me figure out how to reduce the amount of bounce please:

Thanks.
I really do love good design – https://www.splurj.com