When do I have to leave?

[SWiltord11]

I'm currently on the Tier 5 Government Exchange Visa ending on December 10th (stamped Dec 9th when I arrived). Despite having read in several places that this visa allows 28 days grace period, I see everyone on the forums has stated this grace period does not exist - very confused, as the website of the agency I applied through also states I have 28 days.

Anyway I take it this means I have to leave on the 10th. However my boyfriend is coming back to Australia with me but he would like to be here for Christmas. What are my options here? Could I just stay until after Christmas? Or I could leave for Europe on the 10th and come back to London for Christmas for a couple of days with my flight out booked a couple of days later.

Very confused and need to book my flight soon so any advice would be much appreciated.

[The Station Agent]

You have to leave by or on the 9th otherwise you will be in breach of your landing conditions. There is no grace period as such - if you must stay longer you can apply for a 28-day extension but the palaver you will go through will not be worth it.