Koblenz-Winningen is nice enough - I hear good comments about the Greek restaurant, too - but does not meet the IFR requirement. Actually that corner of Germany seems to be full of nice places, it'll take me forever to explore them all. But very few are suitable for the present occasion, given that some participants require IFR.
But mind you, the opener suggested North of Koeln, rather than South.
Yes Stefan - still current.
I really don't think an IFR approach is necessary for this kind of trip. Summer weather in Germany will allow you to do the flight rule change both ways, especially when a big airport with ILS is just next to it and when there are local pickup procedures (EDKB coordinates with ATC when you're on Z/Y plans).
Remains the issue with customs for UK pilots. A stop on the way would be best. I guess Mönchengladbach EDLN would be the most convenient with customs and ILS. The VFR hop to Bonn would only take a few minutes.
The problem with a Customs stop is that it doubles the planning workload. I'd happily fly direct and pay more. The fuel cost totally dominates most flights anyway, and a tech stop burns about another 6 USG i.e. another €40-50 if climbing back to any altitude, and you double that because you have to do it twice.
The hop from EDLN to EDKB is best done at ca 2500ft so not much fuel lost. I don't know what you mean by "planning workload", maybe the 5 minutes it takes to study the VFR approach chart and the VFR map to find a suitable route? 
IFR/customs airfields tend to be boring places. I really don't see a point in meeting at EDDK.
Sure, but getting a bus/train is a lot simpler than doing a local VFR flight.
I guess customs is no problem since the border-police has their academy there
Do you know anything about the cost for customs? I recently heard it was stupidly high, 100 euros or so, because customs has to drive there from Bonn.
Sure, but getting a bus/train is a lot simpler than doing a local VFR flight.
Huh? Seriously? You find locating and studying bus and train network plans and schedules easier than studying a VAC chart?
If we go to Bonn or similar, I would dip into Calais to clear customs, 30 minutes or less turn around. On the return direct Bonn - UK.
Bonn Hangelar costs 130 € for customs, that's the fee the border police charges to handle you outside of a customs airfield. At a customs airfield, it is free of charge.
I don't know why you think a local VFR flight from Mönchengladbach to Bonn would be difficult. Even though I have an IR and prefer it for most longer flights, I try to stay current as a VFR pilot. I don't want to end up like the senior airline captain I talked to the other day who admitted he would not be able to conduct a VFR flight...
