Gatwick Lounges (Non VS)

I am travelling to the Maldives with my wife and 5 year old son - Monarch unfortunatly - the deal via Wexas includes 'free' lounge access:D
BUT the Serviceair lounge in the South Terminal does not admit under 12's - I am being offered a lounge in the North Terminal (Aviance) [:0]
Is that feasable? Can I get from the North to the South in a reasonable time ? Is it even possible (as both lounges are Airside)
BUT the Serviceair lounge in the South Terminal does not admit under 12's - I am being offered a lounge in the North Terminal (Aviance) [:0]
Is that feasable? Can I get from the North to the South in a reasonable time ? Is it even possible (as both lounges are Airside)