I have a non b visa that expires on the 1st of October but want to take a holiday for a few weeks before this date, can I apply for the 7 day extension in advance or does it come in to effect the day I get it? Any help from someone with more experience is greatly apprechiated

The 7 days to leave the country you would get starts at the end of your current permit to stay. But you can only do an application for them a few days before your stay ends.

Ok thanks for that, any idea on when the earliest i can do it is ?

About 5 days should not be a problem.

Ok great, really appreciate that help thanks.

OP, you can apply for the actual one year extension at Immigration 30 days (45 days in some area) in advance, so why get a 7 day extension (which is technically issued by way of being ineligible for any extension class)?

You would get a one month 'Under Consideration' stamp in most areas; then in this case you would need to go back to get the balance of your one year extension added at the end of October.

If you let your current extension lapse, then your Work Permit will also be invalidated as well.

Thanks for that info and will note it for the future, but I have finished working and will return home so i just need around 7 days to see out the rest of my holiday