3 rooms in our house have lining paper and what looks like a thin coat of matte paint. The lining paper looks like its been laid quite poorly with all the sheet lines visible and some peeling around radiators/switches etc. Is it possible to just paint over this? I have seen Zinsser 3 in 1 wallpaper paint has some good reviews, however im not sure whether the lining paper we currently have on the walls is in too poor condition for this? Can anyone advise?