External wall patch up....

Evening! Going to have a go at patching up external garden wall that the render has fallen off, I was going to use a bag of ready mix concrete from Wicks but before I do can anyone else recommend a product I should use or will concrete do the job see attached picture!

Bear in mind I have no plastering/concreting skills what so ever

No concrete wont do the job!! You will have to knock all the old render off and mesh it to hold back any cracks. not a novice's job really. Get a few quotes off a few plasterers that could tackle this kind of job...