Linux

Hmm I didn't know the UK was THIS bad.

Have u tried changing user agent? Get an add-on on Firefox with a similar name and change to chrome. The website will now think that u'r using Chrome. U could even change ur displayed OS if it has that big of a problem with Linux.

Governments should not require the use of proprietary software. I personally would refuse to use it. I don't live in the UK but in the US I think you could easily make the case.

I'm also based in the UK. I don't run a business but have occasionally encountered problems trying to use Librewolf on the web, especially with Noscript on.

I tried to use Qubes to separate my activities into VMs but I found it difficult. So I did my own, less extreme, approach using KVM.

I created a virtual machine which only has Chrome on it. This is what I use for accessing my bank, Paypal and doing online shopping.

I have a second machine I use for Whatsapp and email and finally a third with Librewolf for general web browsing.

Each uses the same VPN service but different servers.

I only use Freetube and Retroarch on my main machine.

This is on a very beefy Thinkpad I essentially use as a desktop in my office. I use a smaller machine downstairs with VNC on it as a remote when I'm sat on my sofa.

If you use Mettle, the phone based bank, you get FreeAgent for free. FreeAgent is a really good web based accounting package that works in Firefox. They gave a useful accompanying API and can do payroll, VAT, end of year and director self assessment. It's great.

Tangential:

I‘m running my own IT company since recently and am transitioning to exclusively using FOSS. I still have some things I need to work around like my iOS phone. It already has a linux successor but its not finished yet. Pretty promising though. My plan is to put a fixed percentage of profits to open source projects.

I think the key part here is that it’s a guess on your part whether using Firefox is the cause. Do you get any specific error when using the website? Or does something just “not work”, such as you click a button and it does nothing?

Also, I’ve run into stuff like this before, and my best bet has been to be flexible about using other browsers to work around issues. I would suggest testing the banking website with Chromium (or even Chrome). If it works, file a bug with Mozilla (https://support.mozilla.org/en-US/kb/file-bug-report-or-feature-request-mozilla) and just use Chromium/Chrome for only that website until the bug is fixed.

This will allow you to still do business, while still participating in open source via a helpful bug report that could end up benefitting others as well.

Also, please feel free to answer if you aren't based in the UK, I assume this isn't a UK only problem, but I'm based here.

Can't speak to the specific sites that you use but I've personally found firefox user agent spoofing results in almost every site that didn't work on firefox suddenly magically working if they think you are on chrome.

I've been Linux in the desktop for years. You really don't have any choice other than to be a little bit flexible.

More times than not it turns out to be a plugin that screws over the site. Here's my general path:

Won't load in Firefox? Disable privacy badger and ublock origin

Still won't load? Try it in a private window with no extensions loaded

Still won't load? Move over to brave.

Still won't work? Disable Shields

Still won't work? Straight to a vanilla copy of edge, (a vanilla copy of Vivaldi would also be reasonable)

Just last night I ran into a problem with my ADP work portal. Things worked fine for ages, All of a sudden my password wouldn't work. I went into private mode My password now works but loading the actual page netted me a blank page

I opened it up in brave and it just worked outright.

Maybe you can use some German bank. They allow one to interact with their API for free. I use GNU cash for it. Though I doubt that you can file your taxes via GNU cash and be aligned with current UK law. You would need to check it for your own.

The UK Government didn’t create a free solution

You mean you must use their software to do taxes or what?

Back in my neck of the woods you either do them on paper (almost no one) or you submit online... They have well-defined APIs and you can use whatever you want (the IRS submission does use some java crap underneath but it's fluid and you can save your progress in an XML file).

Although for most people it's just a matter of logging in, checking that everything is in order, and clicking submit.

Always use a separate Firefox profile for banking needs.

I am not in the UK, but wound up biting the bullet and using QubesOS for my business machine. It's kind of like a more straightforward to use everyday set of VMs. I have the windows qube there for running CAD/CAM and the sadly sometimes necessary Chrome install. I know this isn't an ideal solution, but it is the best that I personally have been able to come up with without going through the headache of dual booting, especially when dealing with either govt stuff, need Chrome for crappy websites my clients sometimes force me to use, or actually needing proprietary software that I have licensed for my business (MasterCam in my case).

When you say it doesn't work in Firefox, does it not work in Firefox or does it say it doesn't work in Firefox? In the later case and sometimes in both, I have found that just changing the user agent string to something chrome based is sufficient to get it working again.

I've found HSBC to be ok using Firefox on Linux. I don't know if they have integrations with any accounting software, but the web access works well, and you can export your transactions for processing locally.

ETA: I've run small business accounting on Gnucash, I found the learning curve a bit steep, but once you 'get it' it's handy.