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Great - glad to hear it was just a DHCP issue. Guess they were both fighting over who was in charge of IP addresses. I'm assuming your speeds have now improved as well?
Well! The odd thing is that on my iPad and wife's phone we are getting the full speeds, but my phone and daughters phone we are getting half speed!
You may want to try forgetting the network connection completely and then re-adding it to those devices. It may be using an old IP address/DNS info etc assigned by the Cisco AP instead of one assigned by your Vodafone router.
In iOS you can tap the 'i' next to the network name and then Forget, in Android just tap the network name and tap Forger.
Thanks, just tried that on both devices but never made any difference, the devices that are getting slower speeds are far superior devices on paper so not following why they are slower...not that I'm that fussed as I don't need mega fast speed on my phone. It's just more out of interest why they are so different.