Yes. I took DS1 to our GP when he was 6 about his bedwetting (he had never had a single dry night and often wet the bed more than once in a night) and we were referred to a continence physio.
I really disagree with the wait until they are 8 philosophy. Children are smart enough to know that other children don't have continence issues and it makes them unhappy no matter how understanding and relaxed their parents are. We never once criticised DS for his bedwetting or even discussed it in front of him and he was thrilled when we took him to the Dr because he wanted help. I hadn't even realised how much it upset him until I saw how happy he was when he saw the light at the end of the tunnel.

Our physio sees people without referrals but the referral can affect whether PHI covers it.