As far as thinking that a nice looking (your proposed enclosure is nice looking) enclosure will allow you and your daughter to see and interact with the tortoise... think terrarium. You know the humidity is right when there are water droplets on the inside of the walls... pretty much.We have lots of places in the US with high humidity. Florida being one of them and their outside humidity only works well for them when they are big enough to live outside
We have many UK members on here too. It's no different there than here when it comes to raising hatchlings. They all need the closed chamber, high humidity.
You absolutely will need a temperature gun where you can measure the temperature precisely in specific locations and the enclosure you showed has another great positive attribute. Height. The reason is because you can use an adjustable stand for the lights and heat so it is the right temperature at tortoise level and you can adjust as it gets larger.
https://www.amazon.com/dp/B091NBDSB2/?tag=exoticpetnetw-20
You also need a thermostatic control so it will heat efficiently without overheating your tortoise.
https://www.amazon.com/dp/B07FYXX9L3/?tag=exoticpetnetw-20
As strange as it sounds, even with a "closed chamber", I have found that some fresh air is essential to controlling mold growth. A small opening at the lower level lets air exchange and keeps mold at bay with the temps and humidity.
My first tortoise had a hole in his "burrow" that he could walk out of and his enclosure never had mold even though it was mid 80's and water dripping on the sides. My little one I kept enclosed with no ventilation and 3 or 4 times in the first 2 months I had to dump the substrate because of white mold. The last time this happened I cut a small hole a bit higher than he could walk out of and the humidity is the same, heat is the same AND no mold after 5 months. This is the basis for my concluding that ventilation IS necessary only for the purpose of keeping the substrate from growing mold. Remember, all food that enters that enclosure has the potential to cause mold growth rapidly even when changed and cleaned multiple times daily in that hot and muggy environment.