gravel over existing slabs

Hello,

I have today lifted the decking area surrounding part of my house.

This was bodged and erected over square slabs. Some of the surface area is made up by a concrete slab on which an outbuilding was built (this was demolished ages ago).

My question is can i lay gravel over these slabs? i can't lift the whole lot up due to the concrete slab mentioned above. It would take ages and i'm not sure i could remove it myself!!!

There are a couple of gullies where the water drains to. If I were to put gravel down is there anything i can use to make sure gravel does not end in the drain?
Also would water drain through the gravel or would it be a soggy mess?

Thanks

gravel will be fine, ad it will drain through it. you can get sheets of perforated sheet metal of different size holes in places like b and q. just cut them to fit and place over the top of the existing gulleys.