Hi Richard

> Some of them are
> plugs with exposed pins, others are the type with a surrounding grey
> casing, with a cutout on one side.

Those connectors with the casing and cutout (non Doepfer-stuff) should
be used only with the equivalent cables with connectors with the nose on
the side. Doepfer modules should be used only with the original doepfer
cables. I know about differences in the holding mechanism of different
connectors of similar connector types: some plugs rely on grip of the
connector tongues itself; other connectors have only a low grip on the
connection and use a notch mechanism.

> Also, some of the boards have a
> short 14 pin connector, but came supplied with a ribbon cable with a
> longer 16 pin connector,

For Doepfer this is not correct. There are Doepfer boards with 14-pin
connectors, but the 16-way cable ends in a 14-pin plug (two leads should
be cut short before the plug). Either you received the wrong cables from
your dealer or you mixed cables of different brands (AS, Doepfer,...).

> Blu-Tack might well be the answer.

Do what you wanna do. I could imagin, that the two year warranty is not
kept up, if you apply Blu-Tack to the module. I would ask Doepfer or
your dealer

Florian