I haven't been to a mumsnet meet up in the area, but I do help organise an NCT Bumps, Babies and Toddlers which has just started. It's at the CUFOS community centre at the top of The Avenue, N10 every Tuesday from 2.30 to 4.30pm. It's a bit out of your way, but you'd be welcome of course.
There is a charge of £1.50 for the tea and biscuits etc and there are toys from babies up to toddlers.
If that's too out of your way; you could try
Jacksons Lane Toddler Group
Jacksons Lane Community Centre, 269A Archway Road, London, N6. Telephone: 020 8340 5226
Tuesday, Wednesday & Thursday mornings 10.00am-12.30pm
Suitable from birth to 4 years.
And finally your local NCT contact is Sam Price 020 8348 8533 [email protected]. She'll be able to tell you when and where there are NCT "teas". I think she might hold them at the cafe in Highgate Woods, but I'm not sure. You don't have to be a member to go to teas.