Not sure about the "professional advice" but my second son was well into school and he was still wetting the bed... I did have a few concerns but kept my patience and tried not to make a fuss. Just stopped him having a drink before bedtime and eventually he stopped. I think sometimes we get the medics intervention too soon, but saying that I suppose there are certain times when maybe it would be good to get a few checks done just to be sure there are no medical problems - all that said, I remember going away with school when I was about 9 or 10 and wetting the bed, it was really embarassing.
My grandaughter was treated at seven. She had a short course of tablets which worked straight away. She took them for a couple of months and has been pretty much OK ever since. It is apparently a hormonal problem and runs in families. Their family doctor was brilliant and made her feel perfectly OK about it all.
Boys (and, so far as I know, men) tend to have less control over their bladders than girls (women) – it's just the mechanics of the process. I think it's not at all unusual for boys of six or seven to wet the bed, sometimes quite often. A sympathetic (old-fashioned?) GP would probably be able to advise whether this might be a serious problem or just a slightly late development.
I think the moment comes when the CHILD cares about the bedwetting, not prompted by parents. Then talk to a sympathetic GP or health visitor and examine the options. My daughter, who slept very deeply, found that the underblanket pad and buzzer worked for her, waking her up in time to get to the toilet.