I can recommend Sally's on Northcote Road. Really nice and a lot of patience with unwilling toddlers. Or children who can't sit still like my younger one ;-)
http://www.sallyscuts4kids.com/?doing_wp_cron=1534710553.1811690330505371093750

I second What about Me (https://www.facebook.com/Whataboutmechildrenshairsalon)

They're fantastic 

I recommend What about me on Kingston Road near Wimbledon in Merton Park.

Porters are amazing. All the kids from the Dulwich schools go there and it’s a cool salon as well. There’s one in Dulwich village and a few others dotted around

If they’re tiny then Trotters on Bellevue. Otherwise Jacinta O’Neil on Nightingale Lane cut kids’ hair. They’re super-friendly and give the kids hot chocolate and a biscuit.

Hi Everyone,

Can anyone recommend me a good hairdresser for my child?

Thank you.