Nope don't get that one. That is outdated technology.
This is the new stuff:
Misol Weather Station:
https://www.amazon.co.uk/MISOL-Wireless-weathercloud-wunderground-weatherbug/dp/B07DKZSF6D/Froggit Weather Station:
https://www.amazon.co.uk/Profi-weather-station-Froggit-WH3000/dp/B06X6JPJ6Q/Profi Weather Station
https://www.amazon.co.uk/dp/B06X6JPJ6Q/1. Yes I"ve heard of all of these (including the old one you mentioned). They are Fine Offset clones. The new one I linked is impressive.
2. Yes these new ones should publish to WU, WeatherCloud, and Met Office WOW. BUT READ CAREFULLY...maybe one of these the manufacture didn't include all cloud services, so check it out to be sure. If you want to publish to CWOP you'll need some extra hardware. You'll need an ObserverIP (UK version with 433 MHz...so one by Aercus probably will work). And then you'll need a Meteobridge. That is that easiest way but not the only way. There is a way to publish to CWOP with just the Aercus (or clone like ObserverIP) and a PC but you'll need to do WU network traffic redirection and then send via WeeWx software.
3. See my recommendations above. You can compare those and read about it here if you search for WS-2902A (or WS-2902 a previous version) which is the Ambient Weather US version. In the US according to analysis I did on WU stations registered it is the fastest growing model for a while now. It isn't perfect. But I'm happy with it, at least till something better comes out like a VP3.
Now you could also get this Aercus model which comes with the ObsererIP device. I don't know what they call it. But the outdoor sensor array that comes with this station is also sort of a previous generation even though still a current model...its been out longer.
Aercus Weather Station
https://www.amazon.co.uk/dp/B00ZVFZUS6/So not recommending that one so much. But it could be cheaper in the long run because of the ObserverIP is included and then you only need the Meteobridge (or do the network redirection trick and run PC software like WeeWx). I don't know if they sell separately the network adapter ObserverIP (with indoor pressure/temp/hum sensor...you'll need that too for any model you want to expand). I don't see it separately listed on Amazon UK. So you may want to reach out to Aercus and see if they will sell you that separately. Shame that Aercus doesn't sell the new version of like those others I recommended. Remember all of these are Fine Offset clones.
NOTE: Be mindful that WeeWx is Linux software. Lots of people run it on a RaspberryPi.
If I lived in the UK what I would do is buy one of the 3 I recommended. Then I would also buy the Aercus (assuming they don't sell the ObserverIP and indoor press/hum/temp sensor separately). Then I would list the Aercus outdoor sensor array on eBay or something and keep the indoor stuff to connect with the newer outdoor array from the other company. Then you recover some of the cost of the Aercus by selling that part as new. I'm sure the Aercus outdoor sensor array will sell easy because those break a lot after a few years and there are tons of people that want a replacement cheap instead of buying a whole new station. And those Aercus sold like crazy and were very popular. So right about now there are tons of people with broken Aercus looking for replacements.
Other thing to realize about the Aercus is that there is no display console. But if you get both and sell the Aercus outdoor sensor then you end up with a display console and with the ObserverIP and indoor sensor and it all works together. You can buy extra display consoles too...as many as you want...if you find someone that sells them separately. What you can't do is mix the UK version brand with US versions brand..because US uses 915 MHz and UK uses 433 MHz frequency bands. So okay to read about the Ambient WS-2902A and the ObserverIP to learn about it all but don't buy the Ambient brand for UK use.
The build quality of the newer model I recommended looks much better in many regards. The sensor are more accurate and precise. It really is a bit better quality stuff. Big improvement. I think it will last longer than the older models. It looks nicer too.