British Airways will switch its Sydney-Singapore-London services from Heathrow's Terminal 3 to the newer Terminal 5 in April this year, after its joint venture alliance with Qantas winds up at the end of March.
The Red Roo and new partner Emirates will remain in the familiar confines of T3, but BA passengers will find plenty of reasons to love the move to T5.
1. Closer to the Heathrow Express and Tube
Terminal 5's stations are newer and closer to the terminal than T3, where you use the central station and then hike along dark and dingy underground corridors.
It's a fast lift or a speedy escalator ride up from the subterranean depths of public transport to the BA departure level.
2. Faster, nicer check-in
While British Airways' Terminal 3 check-in desks are hidden in the bowels of the low-ceilinged ground floor, T5's are on the top floor, with expansive airy spaces, heaps of kiosks and new sunken bag drops that mean you walk straight on through.
Business or first class passengers and frequent flyers will want to aim for the south side of the terminal for the business and first class check-in areas, with staffers who have extra powers to make your trip enjoyable.
Premium check-in is also close to the fast-track security. Even five years after the terminal was opened, though, it's still not always noticeably faster than the regular "slow-track" one. Blame Heathrow, not BA.
3. Larger, better equipped British Airways lounges
BA's main Galleries South lounges are immediately to the right of the fast-track security queue. But you can only turn right if you're travelling in First and heading for the Concorde Room.
Taking the prize for "most cynical profiteering at an airport", Heathrow makes everyone else turn left, go down the escalator, shove through the crowds milling around its shops, and then go up more escalators.
(Don't try to take the lift to the Galleries Club business class floor: it doesn't go all the way up and you'll have to change lifts. The escalators are quicker.)
Once you're there, though, BA's Terminal 5 lounges are really very pleasant — much better than Terminal 3 — ahead of the Sydney Qantas Business lounge on the basis of space, and nearly as good as the Qantas First lounge (though the food, architecture and view aren't as tops).
First class passengers can turn right for the Concorde Room, an exclusive adjunct to the first class lounge. It's recently been taking some heat from frequent flyers for spotty service, so be aware that you have the option of Galleries First too.
Qantas Platinum/oneworld Emerald frequent flyers should pick Galleries First, with dining room, fabulous champagne and space to spread out.
Business class passengers/Qantas Gold/oneworld Sapphire frequent flyers have a choice of three Galleries Club lounges: the main one on the top floor of the south lounge complex, a second lounge at the north end of the terminal, and a third in Terminal 5B.
From the post-security escalator, turn around and head to the south side if you want the spa, head straight on to the north side if your flight is leaving from that end of the terminal, or take the train over to the T5B lounge if you depart from those gates.
Overall, we'd normally pick Galleries South, although the airy terrace in Galleries North is a draw too.
If you want a massage or facial in the spa, head for Galleries South and make sure you stop off for an appointment before starting your trek up the escalators. (Frequent flyers in economy don't get to use the spa unless they're BA Golds.)
As always in BA's Club lounges, you'll need to ask a passing staffer for a glass of champagne. They're serving Taittinger at the moment — the same as in the Qantas First lounges.
4. Better choice of restaurants and shops
There's not much to recommend in Terminal 3, but T5 has two particularly convenient places to eat, and it's a pleasant space to wait thanks to the expansive architecture.
The first, after security in departures, is celebrity chef Gordon Ramsey's Plane Food. Since BA's first lounge food is no Neil Perry's Rockpool, Plane Food is a better bet than the lounges and an excellent addition to your pre-flight routine — and they do an appetising carry-on "picnic menu" service as well.
(If you're missing the Qantas salt and pepper squid, Plane Food has it on the menu.)
The second, on the ground floor of the arrivals area after you emerge from customs, is M&S Simply Food, a small upmarket supermarket that's ideal for grabbing something after you've arrived.
5. Heathrow's best hotel (and restaurant) attached to the terminal
If your flight times are unsociable or you have an overnight layover, the best hotel in Heathrow is connected to Terminal 5 by a walkway.
Australian Business Traveller reviewed the Sofitel in September 2011, and readers tell us that it's been up to snuff in their recent visits.
And we can certainly confirm that La Belle Époque French restaurant is still magnifique, having eaten there several times this year during Heathrow transits. This is the best food at the airport, and if you're a foodie and have a spare hour or two, then nip across to the Sofitel for lunch or dinner.
But beware: don't confuse it with the Hilton "Terminal 5", which is actually a bus ride away, in a different town and further away from T5 than the Bath Road hotels.
What's your top tip for travelling through Heathrow Terminal 5? Share your pointers with fellow AusBT readers in a comment below, or loop us in on Twitter: we're @AusBT.