Hi @Feliss,
Welcome to the Bunnings Workshop community, it is wonderful to have you with us.
The first thing to mention is that you need to ensure that anything you do does not damage, hinder access to or affect the water meters' function in any way.
Assuming the current layout doesn't affect the water meter in any way, the process would be relatively simple. but I wouldn't use concrete, I would use mortar.
Start by creating a base from compactible material by excavating a small trench where the pavers currently sit, then add a layer of around 50-75mm of road base, then tamp it down with a tamper.
Once this stable base is in place, apply a standard bricklayer's mortar to the base with a Brick Trowel, then press the bricks into place, using the mortar to level them out as you go.
Make sure you apply some mortar between the bricks when pressing them in place to create a nice, solid surround for your water meter.
The process is much the same as what is shown in How To Build a Brick Wall. Have a look at this video for a visual example.
Let me know if you have any further questions.
Jacob
