Usual Volkischer Beobachter standard of journalism, the "disastrous" tour and booing they refer to was at the quality of material for his other characters - the "Alan" segment was superbly funny.
Personally I thought his stand up show was very good. The other characters weren't as strong as Partridge. However people went to see Partridge and were willing the support acts off, to get Partridge on.
I've been to big concerts where the support acts were largely booed or ignored not because they were bad, but because people were so so eager to see the headliners, It was the same situation here.