I personally have no experience of water filters, but Paul (one of the blogs I've been following for years) does. See this post of his
https://lifeattheendoftheroad.wordpress.com/2021/11/07/water-water-everywhere-2/

I personally have no experience of water filters at all. But Paul (whose blog I've been following for years) does. I tried to put a link but it wouldn't post. If you go to "Life at the end of the road" and find his post of 7 November 2021 he has a photo of his system. Paul lives off-grid.

You can have as many wi-fi boosters as you like. They obviously won't enhance the overall traffic of which the copper line is capable of carrying, but will make that traffic more easily accessible in the remoter parts of the house. You might look into the Powerline type (which send the signal around your electric mains) assuming you have a conventional ring main. Mobile broadband is c**p in my experience.

I too recommend the powerline technology to boost your coverage, rather than wifi repeaters, which I have also tried.

Essentially, you plug one into the socket by the router, and connect it with a network cable (some of them have socket passthrough if you're short of sockets) and then plug another one in wherever you want extra coverage.

I have the tp-link ones, but, in theory at least, they all share a standard so should be cross compatible. You'd want, for example, one of the KIT pairs, to get the router connection and one extension point, and then as many additional extenders as you want (or, if you have a requirement for a wired connection, you can buy more kit pairs and use one of the pair for that)

Feel free to ask for confirmation that any shopping list you make will serve the purpose

Tim and Ian - thank you both. We had difficulties with getting a powerline system to work at Coven Sud years ago, but I guess the technology has moved on.

We will move the plug-in adaptor (quite new) from South (where it works well) up to North when we go back and try it. If it doesn't work, I will come back to you. Just knowing that plugging lots of adaptors in doesn't create a problem for the system is helpful, as we then know that if the existing bit of kit moved up doesn't work, it isn't because it's an overloaded system problem.

And yes, when Mr BW tries to use his phone as a mobile hotspot to send large image or video files, or architct plans to builders, it is frquently just as useless as a 1MB copper connection. Plus, the EE network was down for 10 days following Storm Arwen, so we'd have had no phone and no internet (on top of no electricity), had we been using EE mobile broadband. We are in range of 2 GiffGaff (O2) masts, so staying with them and sorting the coverage of a crap but stable BT copper connection seems the best bet currently. Until they turn off analogue by the end of 2025 anyway.

Caroline - thank you, I hadn't read Paul before. Reading quickly, it seems he has pretty much the same problem as us with the iron water and its effects, and is using the sand cannister system that needs a lot of space that is all I could find. Confirms my worst fears that there isn't a better/smaller system, but that is helpful too.

It's been a few years since I worked on water treatment systems but I'm afraid I can't think of anything better than one of those cannister based filtration systems for removing iron. You could possibly get a smaller replaceable filter system for just the washing machine but I suspect it would work out more expensive in the long term.
Reading Paul's post I would stress that if you do go down that route the importance of the UV shouldn't be overlooked. Its main purpose isn't to sterilise the raw water from bacterial contamination but rather from growth in the system itself. Unless there's a large throughput of water these units are breeding grounds for Legionella and the like.

Yes, the water filters look bulky. Paul's are in his "generator shed" which is a lean-to on the back of his house. He's off-grid for electricity and has a variety of electricity generation systems and this is where all the wiring ends up. If this is the only solution maybe you'll have to look at accommodating it in your building plans :(

If the powerline adapters do not work you could run external grade network cable from the router to the chosen end point. It can be clipped to a wall or buried in soil and would give you a reliable connection. Only downside is it needs holes drilling through walls etc, but I’m sure you have plenty of experience of that already!

Thanks NiC. I did wonder about the UV, just thinking about our fish pond.

Caroline - those systems hum too, which will drive me mad. Might just have to get to like orange clothes and linen!

Richard - thanks. Mr BW does have a drill bit that is a metre long to get through our walls. It's good to know there is a way to get signal down that end of the house, even if the adaptors don't work.

I have nothing practical to add, but I keep imagining Mr BW making an iron removal system for the washing machine, using enormous magnets. :)

Now there's a thought Verity...