Grout that wide will look messy and crack. Pop to a tile shop and see if you can match the tile and do it properly.

Thanks. I had read that a quality sanded grout wouldn't crack with big gaps but haven't been able to find any. I'll try the tile Shop but I've never seen these before and very thin with a matte finish so not holding my breath.

Not wood, that would just get moisture in it and rot. Not cement or grout that would look unfinished. Either match the tile, or do a border of tiles maybe 10cm in width, along entrance line. A black tile. Cut the angled ones back to form straight line.

Thanks. I'll look at tiles. I should have clarified that this has been a rental for 15 years and was in good condition when we bought and reno but since then various tenants and their pets have done plenty of damage so as dejected landlords, we want to spend as little as possible just to make it presentable again for a couple of years before we put it on the market.