i'm with Paul, skimming straight on the artex is a bad idea..... you're almost a dead cert to get patches blown like that,
stripping it off is usually a workable , if slightly masochistic , plan, steam strippers do tend to work fairly well , although it depends on the age and product as to how quickly it comes off, then you get to have a closer look at what's behind it, and can make an informed decision on whether to renew the ceiling completely, or skim finish what's there.....
i dislike the trend of slapping new boards over it instead of actually doing it properly..... yeah, it's easier, quicker, but it's a half assed job, and you DO lose ceiling height, by at least 3/4 of an inch, which may not be much, but in a room with fairly low (in comparison to the 10-11 foot jobbies in victorian/edwardian premises) ceilings, that does have a psychological impact....
you wouldn't service yer miggy like that, so why your house?