Another few hours today... So, it wasn't, quite, the router config. At least not the software settings. I use a 5G service for my Internet on an EE data-only no-contract arrangement. I know this sounds slightly barking but we have no fibre in our village and 5G wipes the pants off the copper offerings. I also have an O2/Tesco 4G PAYG for my iPhone which is patchy but generally works OK in the garden, the workshop and on the 2nd floor of the residence. Having tinkered with the 5G router settings and got nowhere, I tried swapping over the EE SIM for the O2/Tesco one in the workshop. Stone the crows! I got the RailMaster setup file to download straight off using Edge on Windows 10. I mean, I then got the usual foxtrot about rm_setup.exe was blocked as unsafe by Microsoft Defender SmartScreen and, after I'd switched that off, the AVG AntiVirus quarantine tango, but I was eventually able to download rm_setup.exe, run and do an install. I then got the RailMaster "Key was not downloaded correctly" rhumba, but maybe that's because I hadn't uninstalled that license I was using from another machine. So, it looks as if there is something going on in the EE 5G network. I had a look at my EE user account but, other than handing over cash, it's pretty limited as to what you can do on it. My guess is that EE 5G must connect-in to a backbone at some point and there's probably a firewall in that connection and/or DNS setting that may be interfering with the http://www.rail-master.com/ bit. The catch is EE give me the best 5G bandwidth of all the networks I can access from the residence. Clearly, the O2/Tesco one works on 4G but I get really patchy signal strength and there's very marginal 5G signal so it's quite slow. I've tried Vodaphone in the past, but never again. Not only was the Vodaphone 5G coverage non-existent, but their "no contract" arrangement required a Direct Debit and, having taken 8kB of data off their lousy 4G, proved as easy to get rid of as a dose. Anyway, to keep within the scope of the thread, happy to confirm what we already know - RailMaster isn't finished - as in dead that is...