She'd sound like Cher in Believe
There is deliberate over-autotuning (which sounds like cher) and there is natural sounding autotuning which is just tweaking it.
Wouldn't surprise me if they did autotune her on BGT. Remember the first episode of XF last series when everyone complained the acts were autotuned and suddenly it was removed on the 2nd episode. Syco used it for a publicity stunt.
She can sing though, thats undeniable.