Good afternoon ,
When I try to back up to I cloud with my home wifi network it stopped in the middle. But when I back up through outside network eg coffee shop it backs up very quickly. Could anyone pls tell me.

That could be any number of things. Looking at it on a basic level it could just be your Internet provider does not provide speeds as high as the coffee shop for example. As for it stopping halfway through that could also be something simple like the signal from your' wifi router dropping out occasionally. It happens to me often enough, but often isn't noticeable as generally your router will only drop the signal for a very short amount of time. Thus, when surfing the net it's not obvious. As for a fix, I'm not sure what you can do other than syncing with iCloud when possible at areas with open wifi. Or if you're only really interested in the backing up of your data you may have to look into something like Dropbox or just plug your iPad into your comp more frequently to ensure everything's backed up and safe. Hopefully someone else will be able to give a few more pointers,

Proud owner of a 32GB wifi iPad2 iOS5.