Hi. I had a pair off blue tits nesting in my box earlier in the year. I haven’t cleaned it out as yet as I didn’t think they nested in winter. My friend bought me a camera to put in too, is it too late to clean int now and pop camera in seeing as they seem to be back ?
Assuming you don't live in northern Scotland, now is a good time to do it, while it's mild Winter weather. Birds can roost in nestboxes, so there could be disturbance. Personally, I reckon official advice should be to clean out boxes in Autumn. But, now is better than leaving it til it turns cold again, or closer to Spring when birds are more actively looking for nest sites.