Just as a point of clarity.
I believe Pittodrie meets category 3
Page 28 of the attached regulations state
http://www.uefa.com/MultimediaFiles/...5_DOWNLOAD.pdfQuote:
27.01 Unless stipulated otherwise in these regulations, matches in the competition must be played in a stadium which meets the structural criteria of the following categories as defined in the UEFA Stadium Infrastructure Regulations:
a. category 2 for the first and second qualifying rounds;
b. category 3 for the third qualifying round and play-offs;
c. category 4 from the group stage to the semi-finals.
So we're still good to play at Pittodrie beyond our recent QR3 level and into the play-off round.
However if we were to reach the group stages, we would need dispensation, else have to play at Murrayfield or in Glasgow.

