Leaving aside technical defects, you´re bound not to have WiFi on a route like LHR-HND for at least some part of the journey.

BA and all other carriers use providers with satellites in Ka band that sit in geostationary orbit, i.e. they orbit 'over' the Equator in synch with the Earth, so that they always "sit" on the same patch of land. Because of that, coverage over the Poles is very limited, if not non-existent. Below is a screenshot from Inmarsat:


Global Xpress coverage (inmarsat.com)

While on some areas (the oceans in the south) you can 'divert' some capacity by directing beams, this isn't possible for the actual Poles. (on beams: the way it was described to me is that the antennae on a satellite are a bit like the eyes of a fly, made of tiny sub-parts shaped like elongate hexagons. You can move the direction in which they 'look' somewhat).

BA6, on its way back, flies above the areas of no/little coverage, and at best you'll get a trickle of data; at worst, the onboard antenna will simply be unable to connect to the satellite, since the satellite will be sitting at a very low angle to the plane, and thus there'll be interference in the signal.



Other areas that are usually problematic are India (because, well, the local government is a pain to deal with when it comes to issuing licencing) and SE Asia, due to congestion and lack of satellite capacity.

Things might change once Starlink is fully operational and, crucially, has hardware that is certified for onboard use. Some providers are also launching satellites covering the North, but it'll be years.

As for the rest of the OP's post, well, the 787s in BA have been flogged hard during the pandemic, and some of them are now 10 years old. Cabin maintenance has always been a problem at the airline - compared with, say Lufthansa - and these birds are due an overhaul later in the year.

A wi-fi fault onboard is also a triple pain in the neck. I've got a little bit of experience in fixing satcomm on naval vessels, and there's two ways it can go: if it's software, then you can push a patch remotely. If it's hardware, you better pray it is to do with the servers/cabinets/cabling. It's long, painful and requires specialists to come and fix it, but it's a lot better than an antenna fault. If that's the problem, then it's hangar time... and the suppliers specialist need to come. To quote Walter Sobchak, you're entering a world of pain.


As an aside, and hopefully the OP won't mind the hijacking attempt... But am I the only one who just 'doesn't get' the case for on-board WiFi on a plane? As an user?
I do understand the need for wifi on merchant vessels, on offshore, on places where people are away for long periods of time. But on a flight of 12 hours... I just don't see it. I tried using it for work, on various airlines, and gave up. It's just too much of a hassle when everything is cloud-based and requiring MFA. I remember once trying spinning a Citrix virtual machine on a plane. One hour later I was on the verge of breaking my laptop. And even simple things like SharePoint are a mess. I've ended up saving the documents I want to work on offline, which then eliminates the need for WiFi. And I will not join Teams calls onboard. For non-work related tasks, I've always either found something to watch on the IFE, or I read, or I've downloaded something.