Repairing a doorway corner query?

[ABCwarrior]

Hi Folks,

Been looking after a 1yr old dog(sibling of our one) for a friend, ours sleeps in the porch and it's her space, so I put the other one in the utility room last night, which has no door(but still has fittings inside the jambs for a dog gate which I dug out the shed and fitted).
The spoiled little mutt has always slept on her owners bed and he whined all night, came down to find he'd stripped the corner of the plastering to the entrance. More damage than ours has done since she came home at 8 weeks and was put in the porch from day one(less whining too...)
Anyway- I've peeled off the edging and it looks like(going by Wickes catalogue!)the "plaster flatness guides" they sell has been put on either side. so each side of the corner is separate.
How do I repair and reinstate this corner? Are these strips stuck on somehow and will I need to cut back the existing plaster to attach them? Or should I use a corner type strip? It's not at all obvious how I form a corner with two separate strips so can anyone advise on the technique?
I'm not a plasterer obviously, but am a stonemason/builder so familiar with working mortars etc. Could ready mixed jointing compound be used(I've a tub from a sliding door project I did after xmas)?

Cheers in advance!

 

[PrenticeBoyofDerry]

Is the wall plastered or joint taped?
Is the corner bead made of paper, with two metal strips either side of the angle?

 

[ABCwarrior]

I know I'm jumping the gun by replying to my own post first(!) but this is what I'd have thought would be used, or something like it?:
http://www.tecties.co.uk/ttmm.html

I'm struggling with the concept of forming a corner from two strips, talk about making work for yourself?

If I clean up the area well, apply a few dabs of jointing compound then a beading like this surely it would be far easier to skim the corner each way without trying to maintain a straight edge the way it's been done already?

(The plasterer who did our house(we didn't choose him) is referred to as "Slap Dash" in the area. The work is stunningly bad and we have a corner at the bottom of the stairs which is meant to be 90 degrees but is 85 and 95 degrees from either side!)

 

[ABCwarrior]

Ah....- think that's what it is -paper and metal as that's what it came away as? Would there be any reason I coudn't do it with an edge bead? would it stick out too far?
It's a plasterboard jointed house all round, I know because it was unpainted. it's cracking everywhere anyway better learn how to do a few repairs. Did some INTERNAL taping with the mesh tape at xmas when I put in the sliding doors(all still looking good!!) another builder I know who did some plumbing for us says it's more forgiving than these paper tapes in terms of movement?(s that right?)
So- yes it's plasterboard with paper type joints(presumably with metal for exterior work/corners.

 

[ABCwarrior]

Oh- and the area is high traffic so would a proper metal bead be stronger? Can anyone recommend a decent one and how best to fit it?(ie screws/nails/dabs?)

Ta for any advice again, all our trades have their hidden secrets!!!