Thanks for all the suggestions back before Christmas. Typically, I chose to ignore most of them :=))
I finished up hinging the loft hatch doors so they opened downwards, and to secure them I have made a piece of wood which sits across the doorway halfway down for the catches to latch onto. This can be removed if taking large objects into/out of the loft.
For catches, I made a couple a bit like those supplied with ABRU loft ladders. Where there is a ring underneath the door which you turn and that in turn moves a tang round. I made these out of a couple of rawlanchor eyebolts a piece of metal shaped & drilled to suit and some nuts & bolts. It has made a very secure catch.