I am in the throes of repairing the Tyrolean rendering on my external walls. The patches are various shapes, two of the worst are on corners and are about 2ft by 1ft in area. A couple of weeks ago I saw some builders doing mortar cladding on a large garden wall. I could kick myself now as I didn't ask what fasteners they were using to hold the expanded mesh in place. What it needs, (and and so far this impossible to find), is a 2cm washer with a centre hole the dia of a masonry nail - impossible! If I try to hammer a masonry nail into a brick I end up splitting the brick. I can get the nail in by drilling most of the way then hammering the last 4-5mm into the drilled hole. Am I trying to do the impossible? Is the practical answer that we only hammer masonry nails into the mortar join? This is not always the best option when fixing corner beading and bottom edging. I'm also having to drill a small hole in the edge of my washers so I can nail them. I feel there's something I don't know here!

Definitely rawlplug and screw using stainless steel washers and stainless steel screws.

We do this a lot and it works.

Use big washers, we use 30mm diameter with a 6mm hole.

Oh - and stainless steel mesh too.  Don't use any galvanised stuff outside, it WILL eventually rust.