I'm in my late 40's and from Liverpool.
Previous generations (across the world) were raised on tea, I'd rather give tea than the crappy drinks you see children with.
It was around the 80's when giving tea was going out of fashion and juice came in, that children started with the tooth decay that is becoming common.
Mine had tea, milk and water, now 17-30, so did their peer groups, it doesn't set a pattern for life, or do them any harm.
However, giving them carbonated drinks etc, does.
Being aware of the iron absorption issue and caffeine, is a good thing, so is trying different teas, Black (no milk), Red Bush etc.
This is a non issue.