thanks for the reply.
I don’t have a photo; but if I had to guess I’d say the doorway was about 4inches across and 5inches high. this is about an inch higher than the door on my feeding station.
yesterday I glued a chunky piece of wood across the top of the doorway, taking the height down to just under four inches.
both the hedgehog and the fox appeared on the trail cameras last night; the fox couldn’t get into the modified nest box, the hedgehog stuck his head inside the doorway but didn’t go in.
I’m certain he’d still fit and I put some food inside so I’m wondering why he didn’t go in!
the house had been thoroughly cleaned after the fox went in, so I don’t think it’s down to fox smell