Where were Gustav Sprick and JG 26 based?

I have been given conflicting information about where they were based.

One source said "he was stationed at Fliegerhaus Dusseldorf in 1939"
Another source says "JG 26 was based at Werl in 1939"

And Google can't find any air bases or runways matching either of those names.

If anyone has any coordinates for where their base actually was, I would be grateful.