I've found this week's crossword more tricky than usual. Having difficulty with three clues. 48d - a musical group and coming up, a larger one performing (5) n-n-t. The only word that seems to fit is ninut, as in magpie but unable to parse. 54a: US agent managed to turn round business (5) n-e-o. Finally, 5d: major university opens a computer device, unable to finish cryptic (9) a-b-e-o-s, I originally thought the answer was ambitious but sure 16a is tenderise. Any ideas? Thank you in advance :)