OK I have an update, and I guess a confession. I bottled out when it came to contacting the door supplier. But it's not all bad news. I had a go at sanding the grooves and I think it looks OK. I know I'll have to toughen up and question when things aren't right and I'll try in future. But I can live with this, my doors look pretty good actually. When I oil next time, think I'll just roller the surface and not in the grooves, should avoid the orange stripe effect!