Fitting Q

[RickH]

Erm, I did mention that (perhaps not quite so eloquently ... That said, I was concerned that it might not weather well. Any rain that fall down the wall will settle in the gap. I guess you could use 2mm nylon spacers (as washers) to project the "bevelled bar" forward, that will allow rain water to pass through. If you were to slightly adjust the angle of the other part, it will accommodate/compensate for the 2mm projection.

given me something to think about though. I might be able to use some aluminium angle I have

 

[RickH]

Just to close loop on this ..... I ended up using Keyhole-Slot cutter, and fitted 2 x Stainless Self Tappers as they had nice wide pan-heads.
All worked out as I wanted .. new 'addition' is slightly glossy due to fresh stain, but it will be a perfect match within a couple of weeks.
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