Changing Internet Service Provider (2: on the day and afterwards)

My chosen provider is Zen Internet.  I chose them because I have good experiences of using them in a business environment (they are also "Which?" recommended).  The account has been set up for a while, I have spoken to them a couple of times and was not that impressed.  I couldn't find a way to subscribe to their email service, so phoned them, they were not helpful, so I went elsewhere.  

Protonmail was my chosen supplier - because of the unique service they provide - all encrypted email.  They are not a registrar, though.

For that, I chose Namecheap, no recommendations here, it simply looked easiest to use.  Then I found out that transferring-in was free.

On the day, we had cleared out the huge bookcase that covers up the connection point, and moved it out of the way when the Openreach guy arrived.  After some discussion, the cable route was agreed, and he set about drilling holes and connecting the cables.  Fortunately the grey junction box is now a lot smaller, so quite unobtrusive, and fairly well out of the way.  The service was connected in about 2 hours.  He complained about the Fritz!Box router, but it was pre-configured and just started working.

Next come the home re-configuration:

NAS	This has a fixed IP address and had to be re-connected to the old router, the fixed IP address removed, connected to the new router and the fixed IP address re-instated.
Printer	Connected OK using WPS.  Printing works from the Laptop, and the Ubuntu computer, but not my phone.  This is still being investigated.
Mobile Phone: Pete	Choose the Wi-Fi and connect - no problem
Mobile Phone: Jo	Choose the Wi-Fi and connect - no problem
Tablet: Old	Choose the Wi-Fi and connect - no problem
Tablet: New(er)	Choose the Wi-Fi and connect - no problem
Laptop	Choose the Wi-Fi and connect - no problem
Dell	Choose the Wi-Fi and connect - no problem
Linux	Choose the Wi-Fi and connect - no problem
Powerline	Plug cable into new router and powercycle - all OK.
euFy Doorbell	There is no way in the app to change the Wi-Fi, so the only option is to reset the device and start the installation process from scratch.  This means that the masks have to be set up again as well. 27 Feb: While a shared doorbell appeared to work it was unreliable, we have now removed and re-added the shared account, hopefully it will be stable.
Heating	The heating controller was plugged in to the new router and power cycled.  It got the necessary addresses from DHCP, and eventually connected to the wireless devices it supports.  It disconnected a few times in the following days, but seems stable now.
Car Charger	The car charger did not reconnect after a power failure, a long time ago.  Maybe I will try again.
Battery Inverter	I have received instructions on how to do this.  The data collector has to be reset and provides a weak Wi-Fi, that I cannot connect to because the setup password is rejected.  This is still unresolved. 25 Feb: Two Wi-Fi networks were available, but in most of my resets only one appeared. Eventually the correct network became available (beginning SOLIS_5A), and the instructions pretty much worked. I am getting data on the app, despite the green indicator light not going solid, as it should.
Guest Devices	A guest SSID was created; various visitor devices connect to it when they arrive.  It is on a separate subnet, so there is no access to the NAS, for example.

There may still be more to do, so I will update this post if I need to.