Some technical guidance please:

Our engineers want to put a well cover tread plate onto the floor, dimensions are 2250mmx2250mmx40mm. We can't recede the floor to accommodate the plate.

The manufacturer want to place a 45degree camber edging on each side to reduce the tripping hazard. I think this is too steep and the trip hazard remains.

Are there any guidelines out there to the angle of the slope to minimise the risk?

Evening,

In ship build and repair, we cut holes in decks and bulkheads on a daily basis. We have to place temporary covers over openings as standard. The smaller openings utilise a minimum of 22mm plywood with captive battens. The larger openings we use steel plate equal to the steel that was removed (similar to what you refer to by the sound of it). Sometimes these covers present a trip hazard, as you are experiencing. Unfortunately in our game, where we eliminate one hazard another pops up in its wake.
Where this presents an issue, we place a scaffold coral around the covered area which segregates operatives from the trip hazard. In turn this prevents operatives falling into the hole when our fabricators are prepping / welding etc after having to remove the protective cover. I am not sure if this solution could work in your arena. Otherwise black & yellow painted hazard hatching may work.
I hope this is of some help.

Regards
Alex