XBMC remote connectivity

[#1]

Did you ever get this resolved?
I've just moved from Virgin to Plusent and this is the only issue I'm facing. Normally my Raspberry Pi running xbian 'just works'. Now it no longer shows up as an airplay device, nor can I connect to it via the remote app.
The Pi was obviously set up and working already, the only change is the introduction of the plusnet router. I've tried turning off the router firewall, not sure what else to fiddle with.
If I attempt to connect to xbian via http I get the login prompt, but inputting the correct credentials just brings the prompt back up (as if they were incorrect), so something definitely isn't right.
The oddest thing is that I'm sure it was working the first day I had the router plugged in (airplay at least), I have a feeling it might have been after a Pi restart the next day that it dropped off the radar. The device shows up on the router as connected OK, little green tick and everything.
My Pi is on Ethernet and my control devices are on the wireless connection, in case there's some odd subnet issue.
My router is TG582n

[#2]

Quick update - I can login via HTTP and a browser on all of my devices. But the remote app won't connect, and airplay still doesn't show up. Seems some traffic works, some doesn't? Is the router blocking something?

[#3]

Check which port the remote app is using, because i've noticed some default to port 80 and others 8080

[#4]

The ip & gateway have probably changed, check the settings on the pi/xbmc setup/

[#5]

Hi, thanks for the help
Unless I'm missing something there's nowhere in XBMC to set the ip/gateway, although I can view them. Everything looks as you'd expect.
The Port is correct on the remote app, the one I use has a detect feature, and it even picks up the Pi, but just ends up forever 'connecting'. For airplay it simply doesn't display as a device on my iOS devices anymore.

[#6]

I wasn't suggesting you change them, just make sure they are the same in the client as the box. I would also reboot the xbmc and check again, especially if you haven't rebooted it since changing routers.

[#7]

Yes all as expected, match what the router is assigning.
I've actually just done a complete wipe, put raspbmc on instead of xbian. All set up as it should be, but the issue persists.  Definitely seems like it's something at the router end of things. Is there a setting that needs to be on, or something that needs to be turned off? It's almost like my devices aren't seeing the Pi 'broadcast' itself, could that be something to do with the zeroconf stuff? (I have no idea what it is, but it's mentioned in the remote app)