Unable to Import Manually Created Height Map Tiles

Hi there, i wonder if someone might be able to offer some advice.

I have a landscape that i have created in blender, the landscape is single tile that is repeatable in all directions, so it can be repeated as many times as needed.

I wanted to try and import this as a landscape to produce a Landscape which is ‘whatever’ size i wanted.

I copied the file 25 times and named the files accordingly - Map_X0_Y0.png etc.

However when i attempt to import this in UE it simply says “no files found”.

Am i missing something here? Is there something else being done when maps are exported from Gaea or similar that make this work?

I can tile the landscape in blender and let unreal split it into the correct grids but its a fairly intensive task and i think it would be easier to use individual tile maps.

Thanks