Quick update. Had a mouse again that very night after plugging that hole. Could be he was in the cali already…BUT.. had two more last night. I haven’t had time to check my fix and see if the duct tape is still intact. Will let you know as soon as I get a chance to look.
How annoying and frustrating. We once had a large mouse nest on top of pollen filter in the heater air intake behind glove box. I used wire mesh to block some holes in scuttle.
We used to get loads in our house and trap 40 mice each winter.
Someone told me they would be using Louvre air vents to get under house I didn’t believe they would squeeze through the gaps but stuck fine wire mesh over all of them and no mice since.
Apparently they can get through a hole the size of a pencil diameter !!
I think this is a bit of an urban myth; they can squeeze through a gap the height of a pencil but need it to wider! Slugs however seem to be contortionists on a whole new level as I've sealed up every gap I can find in our house and we still get the odd one managing to get through an impossibly tiny space.