MisterJ
Player Valuation: £30m
Pretty much this, but did it 4:1Sand cement mixture (5:1) dry, brush in, sprinkle with water (not so heavy that the sand gets washed away under the slabs). That's what I've done in the past - then you have to fill 8n the holes.
Don't know if it's the right thing to do as I thunk it up myself, but it worked OK.