Bit of a swine this week - I have major problems with the south-west corner, so help with these four might move me on further :
34A - Puzzle to solve about circles, spinning (6,8)
?????? / ????S???
38A - Bugs with this request for a diagnosis? (5, 2, 3)
????? / UP / ???
34D - Private man flashed clothes, blue (4-7)
(no letters at all) &
20D - Traveller's disease unknown in men having overeaten, smug after treatment (10, 7)
M???E????? / ???????
Some or, indeed, all of the letters cited may be erroneous