I'm having surgery to have fibroids removed and have the marina coil fitted, i have just started my period? will my surgery still go ahead ?

Depends: I usually like to schedule hysteroscopic fibroid resections in the week following a period. So if you are bleeding heavily, your doctor may want to reschedule. If surgery is being done abdominally, like a traditional myomectomy, then it probably won't matter where you are in your cycle. In terms of inserting the iud, it shouldn't matter that much where you are in your cycle.