Plastering internal concrete block walls

I have some ugly painted internal concrete block walls in a flat. Don't want to go to the expense of battens and Gib, I can handle a trowel ok.
The plan is to paint over with Alkyd Flat, fill mortars and skim over with bedding compound (tradeset) getting blocks as flush with each other as possible, then skim over with a finishing compound.
Gap filler down corners where they meet gibbed external perimeter walls.

I don't expect it to look like Level 5, would be happy with a lath and plaster type finish. Not much direct sunlight on these walls anyway.
Main concern is will it crack up or shell off? Any other advice appreciated.

Battens and gib aren't expensive unless it's a huge wall.
If you're going to the trouble of stopping it anyway, why not do it the easy way.
Add 40mm polystyrene and you're even better off.

put thin layers and it wont crack;
It's good to mix some cove adhesive with the tradeset, for the first coat for a good bound on paint;

same mix or just tradeset for second coat;

U-mix is very good compound for the finishing coat.

@johotech - several walls, most have a power point wired internally through blocks. Also a stairwell with blocks both side, think it would be too narrow.
@zak410 what % covebond with tradeset, or just pure covebond firstcoat?

Up to 50% cove adhesive is OK.