raising level of foundation

[vonspritz]

Hi
I'm using trench blocks in a stepped foundation. I now find that I need to raise the level of the higher step by 50mm so that I can run the blocks through at the right level. should I use mortar or a concrete mix? Across the whole foundation or just the width of the blocks?
Your advice always gratefully received
Vonspritz

[welsh brickie]

lay concrete over the foundation

[elwood]

hi

If you have more than 1 course of blocks thicken your beds to suite

Bye