Getting into clubs when not 18?

well, im 17 and all my friends are 18. Im a big chap and i easily look 20. the last day i went clubbing i used a fake irish provisional drivers licence which didnt work, so i had a crap night. my friends 18th is coming up and hes having it in a club. i could use my friends pport to get in but hes probably going too. Just wondering if bouncers ever really look at the actual age of the person or the picture when looking at id. i have pports and i have a real uk provisional driver licence too which could be handy. basically what do bouncers really look at when you go to a club?