There is a possibility for us to move to Sutton (SM1 postcode, 5 minutes walk from Sutton Grammar).

We are in North London now and my son is preparing for 11+ here. We have a strong back-up here as well, so if stay here we are safe.

But what about Sutton? I have registered him for Sutton test, but if he will not secure the place in grammar school there? What are the comprehensive school options for SM1?

There are some strong non-grammar schools but like most areas in London they're oversubscribed and it all depends on where you live.

Personally I'd avoid Stanley Park (now Oaks Park) like the plague. I like the new Harris Academy in Sutton (near the Marsden). I like Woodcote in Croydon but living in Sutton you'd be too far away. I know people with children at Overton Grange and they really rate it, I've not visited though. Greenshaw is good and has a partially selective intake. Glenthorne has a good reputation too.

Not sure if that helps though!