3+ plus months away from the project and I'm now back for my sins! Tried all your advice and still not getting any impression figures what so ever. To summarise...
Used these queries with relevant campaign id's and got following results...
"SELECT CampaignId, AdGroupId, Id, Criteria, CriteriaType, Impressions, Clicks, Cost FROM CRITERIA_PERFORMANCE_REPORT WHERE AdGroupId=" + _reachGroupId;
CRITERIA_PERFORMANCE_REPORT (All Time)
Campaign ID,Ad group ID,Keyword ID,Keyword / Placement,Criteria Type,Impressions,Clicks,Cost
1420007954,56627541275,503005,55-64,Age,0,0,0
1420007954,56627541275,47984193266,uservertical::80097,User Interest,0,0,0
1420007954,56627541275,503006,65 or more,Age,0,0,0
1420007954,56627541275,503999,Undetermined,Age,0,0,0
1420007954,56627541275,503002,25-34,Age,0,0,0
1420007954,56627541275,503004,45-54,Age,0,0,0
1420007954,56627541275,503003,35-44,Age,0,0,0
1420007954,56627541275,503001,18-24,Age,0,0,0
Total, --, --, --, --,0,0,0
Understand any report relying on historical activity will show zero rows/values but from a targeting perspective, should see something. Feels like I'm not passing in enough query parameters or missing something critical
I've attached a screen grab of the UI I'm seeing in AdWords and the impression figure we are trying to obtain through the API.