Patching paintwork on internal concrete wall

I do repair work for a unit block in Brisbane and I have to patch a wall 3m high and 11m long.

The tenant needed to shoot a music clip so he used 2in wide double sided sticky tape to stick wall paper to the wall and then left it there for 2 years. He's pulled the wallpaper off, and surprise, suprise, its pulled off a few hundred patches of paint 2in square over the whole wall.

The wall has had a large number of coats of paint over the years, so even a few coats of paint won't fill the holes. I don't want to strip the whole wall, nor do I want to replaster the whole wall.

Normally I patch holes with Builder's Bog, but I'm not convinced that it will give a decent finish with so many defects over such a large area.

The owners will expect a perfect wall at the end of the job, so no compromises, but I'd rather do it myself than pay someone else.

Whatever I do, it'll be finished with 3 coats rolled on with a long nap roller.

What options do I have?

I find gyprock flushing top coat or final finish is good for this type of thing, it is very fine and will fill even the smallest imperfection. Put it on to the painted wall with a gyprock broad knife wait 24 hrs to dry, sand it with a gyprock flushing type sander and sanding mesh, be sure to feather the edges. Depending on your skill you may need to repeat the above one or more times until there are no low spots and the edges are feathered so no hard edges show. You'll see straight away when you start painting how successful you've been, hard edges that have not been feathered correctly will always show up. A perfect finish is possible with this method, the number of times you need to refil will depend on your skill level.

see if you can get some sheetrock easy sand 45 its easy to use cheap non shrink

Thanks for the advice.

Here's a couple of photos, terrible quality - poor light on a mobile!

Second photo is the smaller of the two walls, bigger wall is three times the size. Each of those brown blobs is a hole in the paintwork.

I think I'll scrape off any loose plaster and then pay a plasterer to put a coat of top coat over it. The owners of this particular unit are renowned for making a fuss, so it has to be perfect, and the tenant has to pay for the damage, so I'd rather pay for it to be fixed than mess around trying to do it myself - its a very large area, over 30 sqm.

Anyone know a plasterer in Brisbane?