15a. The boss's office (11) ???????S?I?
14d. Approves of indications of support (7) ???O???
13d. You've not been going straight if you have to make this up (6) L???A?
21a. Very serious position to end up in? (5) no letters yet
19a. Sounds like a shortage of resin (3) ?A?
If 14 d was to be FAVOURS, then 15a and 21 a could be right folks!! Second letter of 15a is 2nd letter of 14d and 6th letter of 14d is 2nd letter of 21 a.