Our venue in Fareham is the awesome Red Spider Climbing Gym that is a really well-designed bouldering wall that has a TOT appropriate climbing castle and pirate ship.
We use the child specific area to play games as well as the wider bouldering gym which has a TOT suitable family climbing circuit and a fun top out wall which give TOTS a great sense of achievement.
They sell sandwiches, cake and drinks, and have first floor seating where you can watch from above.
There is free parking, however during busy periods it is worth allowing extra time as parking may be full. There is the option to double park and be aware that you may be called to move your vehicle.