Protecting from carrot fly, slugs and mice?

I've grown my carrots under enviromesh for the first time and it looks like they have escaped the fly. However it is a hassle to remove the mesh to pull the carrots and then replace, so I was wondering when it would be safe to permanently remove the mesh? If it's late in the year I may just leave them for winter veg and dig when required. Do you think slugs and mice would be a problem on carrots left in the ground as they seem to be quite a lot a round here   The mice are attacking the sweetcorn and the slugs had a field day on the spuds before they all rotted due to blight - you've got to laugh

I dug my carrots as I needed them last year, I finished digging them in early Feb. I mounded them up a bit and applied slug pellets now and then. I had a few with slug damage and these were the ones that I did not cover properly. Apart from that there were no other problems.