@alanbridgestone If you are on Three UK (sorry noticed you were in Italy). Change the APN from three.co.uk to 3internet This gets you a public IP address. I only quickly read your initial post but I...

@Lee46 ExpressVPN supports PPTP and L2TP? I bit trickier to setup but I've setup PPTPs on Asus routers the 'hard' way. :)

Some providers use a different APN to allow a public IP to be assigned (if available). With Three UK it's a simple APN change ;)

@Terror404 Three Uk SIM? You probably are not getting a genuine real public IP address. This can be resolved.

@Fred.Bonus UK Three SIM?

@lorenzo444 If you are using a UK Three SIM as a 3G/4G provider then you can get DDNS to work (get a real public IP address). If your WAN is getting an IP in the 10. range (or thereabouts) then you...