So after mucking about, convinced it was the Hub6,
Evoke swapped, worked a treat with a 5 but simply no go with the 6... gave up, it's wifi reach was so much better than with the 5, left it connected and went without internet radio .....
then
6 days ago the 6 took and upgrade to firmware SG4B10002244 and on the off chance I tried again to make the wifi connection to the Pure Evoke .... it has worked flawlessly ever since.
Can't recommend the radio enough, and the 6, well that's a six innit.