I've been a bit confused what the DUS flight is about, whether it is aimed at connecting pax or just point-to-point traffic.
Most connections only work well one way with the lack of an evening flight a big minus.
With Eurowings to CGN and Ryanair to NRN from EDI, it looks like most of that Rhine-Ruhr area's point to point traffic from Central Scotland is catered for.
XSB