First up, I haven't read the whole thread, so sorry if this has already been suggested. Get yourself a second hand bottom of the range Synology NAS. It should not cost you more than a few tenners, but even the most basic supports DDNS through Synology's own service ('quick connect', no service fees). Couple that with built in VPN and you can effectively connect to any service on your home network as if you were plugged in at home (ie referencing local IP addresses). It doesn't interfere in any way with your EE SmartHub and also means you dont need to open any public ports, better from a security point of view.
Of course another side effect is that you can also pop in an SSD as local network file store, which is also accessible directly via the Synology apps anywhere (both android and IOS). There are a load of apps you can install in the Synology itself, meaning some of the services you are running on your PC may actually work from the NAS instead.
PS - I dont work for Synology, but I do like their kit. I am sure you can do the same with Qnap etc, I am just not familiar with those.
