Removed wallpaper from plasterboard wall-underneath is a mes

[Maggie1]

I have stripped the walls in the hallway and all the walls are plasterboard.
It is a complete mess underneath with holes from wall plugs (ok have filled them with Polyfilla) but where there is a paint or thin plaster on top of the board, this has come away in different size pieces. Some seems like a layer of paint whereas some of it seems like a very thin layer of plaster. The surface is completely uneven. Also there are parts of the wall that need to be evened up a bit. I was reading some earlier posts and one suggested rubbing down and skimming with Easifill. Can I use this for all these problems?
Should I try and skim the whole wall ? (Try meaning I've never done it before) and if I do, do I have to use 2 coats? or even better is there some miracle paint been invented that will cover all this?
I am intending to use lining paper after because I want a smooth finish.
Bit of a tall order but we have put lining paper on other walls and the dips show through. (and those walls weren't nearly as bad.
Hope someone can help.
Cheers

 

[PrenticeBoyofDerry]

Do you have any photos that you can upload that shows the extent of the problem?
If the walls are slightly uneven and there is not a great deal of damage, easifill can be used and sanded down.
But if the walls are damaged and all over the place, I would suggest a two coat skim.
But sounds like you do not have a lot of plastering skill or knowledge, sorry if that sounds harsh.
If you decide to DIY it you could make a bigger mess than it is already is, Plastering is a skill and practice is needed to attain a quality finish.
Not trying to put you off DIYing but I would recommend you get a pro in to make a good job of it.
But lets see some pictures first and access what you have.

 

[mickthebrush]

get a plasterer in might cost you a few £££ more but will take a few days less

 

[ajrobb]

It's amazing what you can conceal with Easi-fill applied with a plastic spreader and a rub down with sandpaper.