Hi Simon, I've had a skeet at the heli pins in your link and I have used them to repair cracks in masonry walls in the past.
They are used with a chemical resin to bond them into slots which one has to cut across the crack with a diamond disc on an angle grinder. Clean the slot out,apply resin and then bed the heli pin into the goo,fill crack out to level with more resin or cement and the job is a goodun'.
They provide a simple but very effective method of stabilising masonry defects and the end result looks very much like stapling or stitching.....The mics look a good find,quite tidy and not knocked about too much
![:thumbup:](https://madmodder.net/Smileys/default/happy0034.gif)
...... OZ.