Devices not made discoverable on local network with BT HH3

So we're on BT infinity and have the HomeHub 3. I've experienced a lot of problems with devices on my network making themselves discoverable though.
It started with our network printer, and epson stylus sx515w, I configure it over the network and it prints fine, for a couple days. After that the computer (tried on various versions of windows) no longer finds it. I have to delete the printer and re-add it. The printer is not discoverable on the network and I have to manually specify an IP address. Even when doing this it only sometimes then works. I assumed this was a problem with the printer but I realised there were more problems.
If I run a mobile mouse server on my PC for using an iPhone as a mouse and keyboard over wifi, it can never find my computer (it's supposed to find servers on your network automatically) and again I have to specify the ip manually. Once again this only works some of the time.
I have similar issues with XBMC remote app for iPhone. I have run XBMC on three different devices, on three different OSs all connected to the network and the app never discovers them, I have to specify the ip. Once again sometimes this won't work at all either.
Finally there is my chromecast. I set it up, all was working fine for a few days then suddenly the chromecast was not being discovered by any of my devices anymore (iPhone, iPad and windows computer). The chromecast is connected to the network just fine, I can see it on my routers control panel but it simply isn't visible to my devices. Even after a factory reset of the chromecast and reconnecting it's STILL not being discovered by devices.

After all this I can only come to the conclusion that my router is somehow limiting devices from broadcasting themselves or something, the only thing in common across all these issues is the router. Does anyone have any ideas about how I might rectify this? Is there some kind of firewall in place that is limiting this kind of stuff? I can't find anything in my routers settings that will make a difference. And before anyone asks yes I have tried making the local ips for the printer and such like static but this makes no difference.

Edited by deleted (Wed 04-Jun-14 12:04:30)

When you give these devices fixed IP addresses, you are using numbers in a range that is excluded from dynamic allocation by the router DHCP?

No, as far as I am aware my router won't allow me to do that.

I have a client with a BT HH and wifi printer.
Every now and then the printer drops off. A re-boot of the HH brings it all back to life - have you tried that rather than removing/adding the printer?

Not much help I know!
If you are happy it's the HH and it's on the latest firmware etc. then it might be time to try a non-BT router...

In reply to a post by cainy393:

No, as far as I am aware my router won't allow me to do that.

The router will have a range of addresses it can allocate using DHCP. On HH3B that can be configured under advanced settings, Home Network, IP Addresses.

By default it is 192.168.1.64 to 192.168.1.253.
If the printer won't work with dhcp you should give it a static address like 192.168.1.10 (192.168.1.xx where xx is less than 64).
subnet mask 255.255.255.0 and gateway 192.168.1.254 (again, assuming HH3B defaults)