Hi
I can't find that video. Maybe it's gone.
Anyway, what have you tried so far from the above?
Here's what I would do. Apologies if you know some/most of it already...
1. Remove the pads from the caliper and the wheel from the bike. Are the pads in good condition?
2. Use a plastic tyre lever or similar plastic tool to push both pistons back all the way into the caliper.
3. Put the wheel back in. Make sure it's in the dropouts correctly aligned (put the bike on the ground before tightening the skewers if you've had it on a workstand). Look through the caliper and see if the edge of the disc rotor looks aligned in the middle of the caliper. If not, loosen the mounting bolts on the caliper and make it so. The other thing to look for at this stage is if the disc is rubbing anywhere on the caliper body - the disc should be centralised as much as you can with respect to the slot it rotates through on the caliper. Tighten back up the bolts incrementally (not just tighten one completely and then the other). Be careful with torque if the bolts are going into carbon, although Whyte told me today that my bike has alloy reinforcement inside the carbon fork for the brake mounts. I use a torque wrench even on the non-carbon parts of my frame.
4. Put the pads back in. Squeeze the brakes on the rotor a few times. You may already have solved it now. If not, look through the caliper "window" again as you rotate the wheel. What do you see? You should be able to see the gap between the pads and the rotor.
5. If the rotor is only contacting the pads at one or two spots as the wheel rotates, then the rotor needs truing as I talked about before. You can also get an idea of this by just holding something like a plastic tool, near to the surface of the rotor as you spin it and monitoring the gap/listening. Brace the tool in your hand against the caliper body.
6. If the rotor is true, but it rubbing just one of the pads, then you can again try your loosen mount bolts and retighten while braking approach. Try a couple of times with different amounts of brake pressure. Again, make sure you tighten both mounting bolts incrementally.
7. If this doesn't solve it, and the rotor is still rubbing one of the pads, then put on some clean gloves. I mean really clean gloves. Note which pad the rotor is brushing against. Hold the rotor either side of the caliper and push/pull gently against that pad. Not so much as to bend the rotor (which would have the opposite effect to what you want), but just to give the piston a little nudge back into its recess.
8. If this still doesn't work, then one thing you can try is to clean the pistons, in case they are sticking. I misunderstood your original post and thought that the bike was brand new, but I now realise this probably isn't the case. You have to be careful cleaning the pistons. They way I've seen recommended is to just carefully expose them from their recesses by operating the brake lever while neither the pads nor wheel is in place, and then resetting them back in their recesses. You repeat this a few times. I've personally used solvent once on them while exposed (methanol was all I had). That's not recommended, nor is any solvent because of the piston seals.
9. When you are finished, if you are at all worried that you got the rotor dirty, clean the rotor with iso propyl alcohol or disc rotor cleaner.
I've had success with a mixture of the above approaches in the past, although mine are Shimano XT and SLX brakes on my MTB. I've not had to touch the ones on the Whyte yet.
My Whyte is not the same as yours either, and has different brakes (still hydro discs).
