Can anyone help me with the last two clues please?
20d: Some elite academic betrayal, maybe, better for logic? (9)
I have O - T - E - - - N
36a: Openings in colonnade showing dull interior (7)
I have - - O - A - A
All the letters appear to be correct. For info, the 7th letter of 20d forms the first letter of 36a.