Has BA thought about starting a 2nd daily SYD flight LHR-PER-SYD!?
 

First is the B789 engine issues with RR resolved yet!? I just read that QF's most profitable route and highest load factor is the daily LHR-PER service which continues onto MEL. Since BA only serves SYD daily via SIN how about replacing or launching a 2nd daily via PER!? As far as I can see this reduces the flight time by ~1 hour west-bound against the winds.

Can non-Australian operators operate 8th freedom flights in Australia?

I think that the hope that there is traffic scope for a second LHR-PER is currently over-optimistic. QF rightly filled that hole, and in all likelihood, they will also be the ones offering a nonstop SYD-LHR whenever this will become technically possible (and that won't be very long).

I don't imagine the margin on the LHR-SIN-SYD is massive especially in the rear cabins.. prices are very competitive in Y and there must be huge pressure from regular pax just searching for cheapest flight LON-SYD and not worrying too much about carrier.

Another LHR-***-SYD route could cannibalise the main route ?

I think that is the point-the premium cabin(s) are often full. I think demand is possibly there via PER.

I can't see any tickets for the QR SYD-CBR hop - so my guess would be not at present.

LHR-PER in BA CW (or WT) sounds unbearable.

Likewise you can't book BNE-CNS with CX

This has been a big bone of contention with SQ, who wanted to fly SYD-LAX and kept asking permission from the Australian Government, and were getting turned down, presumably to protect QF. QF J fares on SYD-LAX were often as much as SYD-LHR, so I imagine it was helping their profits!
The above is a few years ago now, so various things may have changed - but I've not heard of the restriction being relaxed though.

I think some time before Qantas announced the launch of this route there was a thread here that pointed out that BA was probably well placed to operate LHR-PER non stop. Economics presumably went against that gamble. More realistic is that Melbourne could be better plumbed into the BA network, such as LHR-BKK-MEL.

Which would be quite an upgrade on the BKK route with the worst flying times and equipment on the network

Currently the lowest base fare for business on QF for SYD-LAX RT ($4906 USD) is significantly higher than the lowest SYD-LHR RT ($3973 USD)
The fares on SYD-LAX have routinely been higher than SYD-LHR.
In F the difference is even greater ($11732 USD) for A class on SYD-LAX compared to ($8908 USD) for A class on SYD-LHR, that is possibly also because QF operates the only F class nonstop on the route.

Before worrying about the regulatory issues, where exactly does the demand come from? If all LHR-PER-SYD does is cannibalize LHR-SIN-SYD, what sense does that make to BA. Even if BA were authorized to sell PER-SYD to fill the vacant seats from the PER O&D traffic, how much of a market is there for a one-off inconveniently-timed PER-SYD flight on BA?

One of these threads?
https://www.flyertalk.com/forum/brit...have-done.html
https://www.flyertalk.com/forum/brit...australia.html
https://www.flyertalk.com/forum/brit...es-2015-a.html
https://www.flyertalk.com/forum/brit...r-tpe-per.html