Patching external render

[Mr Gear]

Hi, hoping for some advice please.

A while ago a window was fitted to front of house which unfortunately caused a few palm-sized areas where the render was damaged.

The fitters did fill them with some sort of mix, not a great job in my opinion, though to be fair I guess not their speciality.

Not only do they not match the surrounding render (smooth rather than a slight texture) but they seem to be washing away slowly in the rain... though that might be due to me holding off painting them, which I didn't do as they don't look right.

Its nothing too large or serious but they do need sorting before I paint the wall.

Would it be better to scrape it out and start again?
If so, what mix should I use, and should I add anything to help it bond or waterproof?

I understand from reading here 'normal' pva shouldn't be used, but the waterproof pva / sbr (?) seems to come in 5L tubs only, making it quite a pricey task for such a small job.
I've spotted Everbuild 204 in toolstation for a fiver which appears ok from the specs, but maybe I'm barking up the wrong tree.

Any help gratefully received as always.

 

[Crystalclear]

It's just to give you an idea of procedure.

As far as the pva goes, Pva is sometimes a choice if you don't want the wall sucking the water out of the concrete faster that normal.

 

[Mr Gear]

Thanks for the video Crystalclear, interesting but luckily way way more than I need to get done!


Still hoping for suggestions for (cheap or small quantities) suitable pva-type products....?