I was advised to do a "Long Final" by the tower staying North of Dundee.
How on earth can you do a "long final" to Dundee staying North of Dundee?
The airfield is south of the town. It would be very unusual for Dundee ATC to want you North of the airport - from the AIP:
flight in the ATZ to the North of Runway 09/27, and the extended centre-lines, is not normally permitted.
And the published circuit directions are:
Circuit directions: Runway 09 - RH; Runway 27 - LH.
so arriving aircraft should therefore be South of the airport.
This information is also in Pooleys (which you claim to have been reading).
Or maybe you just got your North and South mixed up? A basic mistake, when you've been travelling North all day, to think that what is in front is North. Not very good situational awareness, though.
FBW