It does look like a dns issue. Had to set wan and lan dns to googles then factory reset tv. Had a few issues but they seem to be slowly resolving themselves. One thing that could help is if you could setup a secondary dns on the tv and force dns cache clear.
Netflix is now working more reliably but not 100%. Channel5 app does not stream anything at all. Bbc iplayer and play movies always work.
I will monitor netflix for next few days.
Thanks for the feedback.