Just fitted a new Stroker Trail and the lever moves about an inch before the pad contacts the disk – on my daughters bike (for which I bought some used Trails) the travel is about 0.25″ before they bite.
I’ve tried bleeding it but its not made a difference.
The pistons/pads seem to be retracted all the way and have a fair distance to cover before they get to the disk – should this distance reduce with a bit of use?

I have not seen the new ones. But my older ones look like this:

Rotate the knurled nut in the round recess with your thumb and fore-finger to change the lever’s throw.

If you mean the bite point is too far in the lever travel, just take the wheel out, pull the lever half way, release it and put the wheel back in. This will bring the pads closer together. If the bite point is still too far into the travel, repeat until its ok.
I have mine set up so that the pads are as close as they can be without causing drag on the disc.
If you go too far, just use something plastic (you should have got a black spacer thing with the brakes) to prise the pads apart and start again.

buzz – that dial is a reach adjuster, it has no effect on the lever throw, only how far it starts from the bar, it still pulls the same amount before biting.

All that does is move the lever closer to the bars, it doesn’t affect the pads.
My problem seems to be that the pads simply start too far from the disk!
I’ve tried re-aligning the caliper so I’ll see if that helps.

Helloooooooo, I’ve just given you the solution! 😆

“buzz – that dial is a reach adjuster, it has no effect on the lever throw, only how far it starts from the bar, it still pulls the same amount before biting.”

You are right. I didn’t read the OPs post properly. 🙄

Helloooooooo, I’ve just given you the solution!

It seems you may well have done…. much better now.
Thanks 🙂