Home sharing pauses on iPad and iPhone but not Apple tv

I hope someone can shed some light on this.

I have a Windows PC in the garage with an Ethernet wired connection to an AirPort Extreme, the Windows PC is acting as a media server and runs the latest version of iTunes.

home sharing has always worked but recently it has been giving me problems. I hope someone can help as it is a real pain.

OK....

Home sharing works great to the 4 Apple TVs that I have, the progress bar for loading every film that is stored locally is very quick.

note I am not streaming from the Internet just from the local PC, their is acces to the internet though.

Anyway Apple TV is great.

The problem has recently started with the IPads and Iphones that we have, some movies pause repeatedly on playback on iPads/iPhones . However some movies work ok.

John Wick in HD is an example but it's not just HD films predestination in SD does it too, although I did buy predestination in HD too and that did the same thing there are unwatchable even on new iPhone 6s.

These movies stream brilliantly to the apple TVs even if I run all the Apple TVs at the same time so it can't be the network speed as all the network is wireless bar the Ethernet to the PC.

On the IPads some movies fill up the bar a tile way in advance of the current paying position of the film but some don't and these tend to be the ones that pauses repeatedly.

I have tried firewalls on and off and disabling IPv6, I have tried streaming these films from a different PC with a library that on contains one film to exclude effects of a large library and these problems still exist

one thing I did notice is that iTunes creates lots of instances of mdnsresponder ipv4 loop backs when playing these films to the iPads, also the Apple TVs run bonjour services when home sharing and none of the iPhones or iPads run any bonjour services that show on a network scan.

I Kkow I have rambled a bit but any help would be appreciated as home sharing used to run great.

thanks in advance.