It is all down to your college...
My college does it a week behind - so that you get the ema of the friday of the next week that it was for. Means that you get it in first week of holidays but not first week of coming back.
Bonuses I got in middle of January; start of July and I am guessing I will get another at end of September.
As for start of year - it is on your own to get it in - if I get my college to sign contract straight away - it will be done straigt away. Some people wait until the backdate deadline of end of September (my college only)