My biggest worry about this is that the person that bored the cylinders, after sleeving, may be the same guy that fitted the sleeves. Is there any reason to believe that the sleeves are a tight fit and will not have hot spots or even be loose? I think it would be safer to start again from scratch. For what it`s worth, Lister used to make oversized pistons in 10 thou increments up to +40 thou, but you already know this so I`m trying to teach my mother to suck eggs.
I suspect you know how to shrink a seized bearing by running a bead of weld on the inside. I have never tried it on a cylinder liner but in theory it should work just the same, might be worth a shot if they have fitted the largest liners available.
Bob