I don't know anyone who has an NHS dentist. Not a soul.
DDs and I go twice a year, once for a dental check up, once for a hygienist visit. We don't need any more because we really look after our teeth. I'm a bit paranoid about keeping teeth clean, and we all have both electric, and sonic toothbrushes, a Waterpik (DD2 has braces, they are great for that), and Tepes.
No way on earth would I risk going once every five years. Oral health is extremely important.