Moondog55

What's the voltage drop over 140 metres?

Yes to that if you live in the Western suburbs, especially around the racecourse area, some parts of Melbourne still have exposed basalt, it depends on what side of the river you are. Only way to tell really is to get a geologist out and have a proper soil test done; not cheap sometimes, I can't remember what we had to pay.

Brings up another issue then. If the posts supporting the existing structure aren't set deep enough then that alone might make the roofing of this area unviable. To the OP When we had our roof done we had to go down a minimum of 1000mm in a 450*450 hole to satisfy the building inspector, needed to be this deep to resist upload; do your existing posts meet the minimum uplift requirements?

I tend to agree Metrix, luckily I have a qualified mate to double check my work for me and I did buy the requisite manuals etc. Re the bugles the advice is that for this purpose they are functional equivalents. Regarding the OPs query; how are top plates on a double brick wall secured or is the weight of a tiled roof "enough" to stop uplift given the extra load an attached fly-over roof will place on the existing structure?

If it helps we used short bugle headed batten screws with washers on ours rather than 10mm coach screws, the hold down rating is about the same; either is so much stronger than the couple of old skew nails that are holding the rafter to the top plate in old construction, we predrilled too in 80YO hardwood

Strange when I thought that Hyundai and Kia were the same cars with different shells.

Would it be simpler and cheaper to just add two more brackets with the correct bolts? We had access to the inner walls when we did our flyover which made things a lot easier but these are supposed to be fixed to the full frame of a stud wall which then connects to the ground.

How many brackets have you used?

Better off uploading direct to this site. I'll leave a qualified sparky to comment on the installation