Only 50 yards more with driver than 7 iron!

That isn't that odd in terms of gapping. I'm sure lots of people hit 7 iron 150 and driver 200, so still a 50 yard gap. You see that a lot with people who have an over-the-top cutty kind of swing, because with driver it produces a big fade that loses distance.

I was at a TopTracer range last night. The range is only around 150 yards long to the back fence though. In practise/range mode, the top tracer was still measuring it as it hit the fence, so I had some that were 153 carry, 151 total distance as it came back off the fence. Then I changed it to 'long drive' game mode, and this mode it estimates the total distance it would have gone without the fence being there, by extrapolating from the ball flight I guess. Slightly more use but still guesswork! Couldn't really take that as gospel.