I am not always to savvy when it comes to those European measurements, so I am thinking that you are talking about 4 square meters which in US terminology would be about 6 FT by 6ft ? Well anyhow you can explain to me later. I would try to order from a place in the UK because you will have a better chance of getting exactly what you need in the way of ballasts. What voltage do you run on anyway?
Your list is just fine at this point. One question I have though is, if this is your first time then why do you want to grow hydro? It is a great way to grow, but it takes allot of time to get things down with the system, and if you haven't grown before then you will have a double learning curb because why you are trying to learn how your hydro system works you are going to be trying to figure out your plant and its different stages, feedings, sexing and so on and with the hydro, PH, PPM, water temps, grow mediums, hydro style and so on. I don't want to discourage you, just want to give you my input.
Also, last question, do you have a goal in mine in the way of yields that you want? This can be good and bad, first grows usually are difficult and you get what you can, but if you want to achieve a certain goal at some point you want to make sure that you are getting the kind of set up that will allow you to achieve it when you get everything learned.

Adieu