I used to do pub refurbs all over the country years ago and I always used 8x2 expamet sheets fixed to floor boards with galv plasterboard nails then latex leveller over the top, then tiled with x7 and ardion 90. You'd have to rip the whole floor up to get it up, I went to a boozer I did 20 years ago and a large floor area of reclaimed quarries was still down and not a crack in sight and the place had been refurbed a few times since.