Hi @DianaP it seems as though you are getting somewhere at last 
. From what you say, it seems as though you have the Livebox and your Asus VPN router sharing parts of the same IP address range 192.168.1.x, with each box being set up to use just it’s part of that address range. A much easier way to get this all working is to connect the cable between the Livebox to the Asus VPN router to the WAN port on the Asus router (the separate blue socket on your router) and enable DHCP on the Livebox. Then set the IP range on your Asus VPN router to 192.168.2.x. Of course if you get it working properly the way you have then that works for you. The one downside to this is that you won’t be able to access anything connected to your VPN from outside the Asus box … although I think that’s a positive. This setup should also make it more difficult for UK based entities to detect that you’re outside the UK. With your setup, try opening the following website in a browser connected through your VPN
You’re IP address detected and any DHCP servers detected should all be UK based. If there are any that are not, then you may have issues.
Edited just to say that I’m no networking expert by any stretch of the imagination. I’ve just learned though trawling the internet and figuring out how to do this.