I have been to Manx Museum and Manchester City Centre Library. The microfiches aren't indexed, so unless you know what address to look up, you have no chance, because of course they are not indexed. The MM has photocopied the first page, giving the area that is covered by each fiche, so that is a help, and of course the IOM set is not awfully big so it would be possible to look all the way through it. But I honestly don't know how you would look up anything in city areas.

Updates are regularly being posted on the census site.