Not sure if I understand your question. You should have...
Scart Lead between the SKY (TV) Socket & TV Scart Input.
Scart Lead between the SKY (VCR) Socket & DVD Scart In/out.
And for completeness (if available, to solve SKY overiding DVD output when both are active)..
A Scart Lead between the DVD (Output) and TV Scart 2
On some old Amstrad models the SKY (TV) & (VCR) sockets were labled back to front. Not sure if Grundig ever had the same problem though. But If the above doesn't work try reversing the connections to the SKY scart sockets.
Cobweb, October 2005