Animating the content inside a clip-path or mask

Can anyone tell me if it is possible to animate an element inside a clip-path or mask? I am new to hand coding and I am trying to recreate some effects I use regularly in Adobe Animate.

I have some svg text which i want to animate a gradient background into to reveal the text.
I created a mask and clip path to show the gradient but when I try and animate it then the whole thing moves as the clip path moves with the gradient and i end up with moving text.

Any hints, tips, examples or links will be gratefully received.