It sounds like you've prepaed yourself really well, so that is great!
Here is a link to a care sheet for Hermanns
https://www.tortoise-protection-group.o ... 014New.pdf
but even better, here is a link to a great site about Hermann's tortoises, including information on the various sub-species, care sheets, etc. The chap who runs it lives in the USA, but the advice is just as relevant to the UK:
https://www.hermannihaven.com/
Regarding your set-up, it sounds fine, but I think most people prefer a soil-based substrate (ordinary sterilised topsoil soil mixed with children's playsand), because it most approximates the substrate that they live on in the wild (sandy soil). Coco fibre can work and I know people who use it, but it gets dusty (although so does the sand/soil substrate).
Your heating and lighting set-up is slightly unusual, but I think it could work. We don't often recommend a ceramic heat emitter, as they don't give off any light, but you have the LED to compensate for that. For your 12% UVB fluorescent tube, do be sure to get a reflector to clip on it, because that will direct more UVB rays down into the table and it will also protect your eyes (which can be damaged by looking directly into the tube). Whatever you use, what you are aiming for is the brightest possible environment with the right temperature (think really bright summer's day). So directly under your heat source, and at the height of your tortoise's shell, you want a temperature of around 30C, and at the cool end of the table you want it to be about 20C. And there shouldn't be any need for heat at night (they quite like a drop in temperature at night), unless the temperature drops below about 13C or 14C, especially for babies.
So it's important to be able to measure the temperature under the heat source accurately, and a thermometer mounted on a nearby wall will not give an accurate reading. The best ones to use are the digital fridge/freezerthermometers with a display unit and then a probe on the end of a long cord. like this:
https://tinyurl.com/yayushmc (but there are loads if you just google them). Be sure you get one with a Max/Min facility so that you can see how hot or cold it got since you last re-set the function). You can then hang that down so that the probe is hanging under the heat source at the height of the tortoise's shell.
Also, you need to be able to raise and lower your heat source. The ambient temperature in a room has a big effect on the temperature in a table, so on a cold day, you will want to lower that heat source so that it is closer to the tortoise, and on a hot summer's day you will need to raise it so that it isn't too hot in the table.
With Nutrobal and limestone flour, it's best to wet the leaves you are feeding and sprinkle the powder on them so that it will stick. If you leave a bowl of limestone flour out your tortoise will just track through it and it will be gone and spread all over the substrate before you know it. What you can do is to leave a cuttlefish bone in the table for him to nibble at will. Some tortoises won't eat cuttlefish bone until it's been sitting outside in all the elements for a month or so, and beginning to look horrible -- lol, then they devour it.
It is great that you are going to grow your own weeds. Several sites sell seed mixtures especially for tortoises, and I can give you a link if you are interested. I also think the 'furniture' etc. that you plan to put in the table sounds really good. Tortoises get bored if they can see from one end of hte table to the other without interruption, and then they get lethargic, so lots of things to walk around, under and over are great.
Sorry to have gone on at such length! I'm sure you're going to be a great tortoise keeper. Do ask any more questions, ad please post photos of your little one when it arrives (we never get tired of looking at photos of tortoises!).
Nina