Good obstacle course for kids in London?

[TheYearOfSmallThings]

My DS(7) is watching Ninja Warrior Japan and now wants to train himself on a challenging obstacle course. He's too young for the Ninja Warrior centres but I feel there must be outdoor obstacle courses that would be challenging but achievable for a 7 year old?

Does anyone know any? We're in London and not averse to travelling to random locations in other suburbs.

If you do searches online for Parkour activities you might be able to find stuff outside. I have seen this sort of stuff in small parks in Scotland but nothing where I am in London (NW).
Flip Out used to have one inside that kids could use.

Air Thrill airthrill.co.uk/uk/london/
Inflata Nation Colindale
Cloud 9 Leisure
The Labyrinth Challenge is coming close to London later this month
thelabyrinthchallenge.com/events/

Thanks for these - yes, we used to have these in parks near us in Dublin, growing up. We didn't have playgrounds though.

InflataNation looks like all DS's dreams come true, we will definitely give it a go

If you are north London, there is a Ninja Warrior in Watford and a Cloud Nine in Hemel Hempstead

Sorry, just noticed you said he was too small