Hey mate, great to hear from you :)
I haven't had that exact situation, but I have had a few parents get their back up and being told their child could benefit from training and they tell me how naturally talented they are. I'm sorry luv, but little Billy will only get so far on natural talent when the kid down the road who may be slower than him today has been putting in the work for a year and at the next meet absolutely smokes your naturally talented but bone lazy kid.