Cement Question

[skybluescooby]

Just a quickie, i was going to post this in gardening but it looks slow in there tonight.
I have just put up a fence and due to uneven ground level i have a gap between bottom of fence and soil.
I don't want to build the soil back up to touch fence as the area is prone to flooding in the winter.
I am going to put a row of driveline bricks to tie the fence in with the soil if you know what i mean. My question as simple as it is is:
What mix of sand cement do i need to bed these in. Is it best to buy a premixed bag and add water or buy cement and sand separately ?
Advice appreciated as my 4 year old wants to let the rabbit out in the garden to roam and with a gap i can only envisage a flat rabbit

 

[noseall]

why don't you just pop the panel out and dig a gravel board in instead?

 

[skybluescooby]

Because due to flooding the board would soak up the water and in turn up the fence, the previous fence only lasted three years due to this problem.

 

[JohnD]

Concrete gravel board.