Giving notice and holiday pay etc

[The Tea Boy]

Afternoon all,
I've handed my notice in at work because I'm leaving to set up my own shop, the boss is fine with this and understands, but he wasn't too happy when I explained that I'm due my holiday pay for the period Jan until the end of April ie about 6days pay.
Now he is interviewing other people and I think he may ask me to leave a week early to use my holiday, so as to save himself having to pay me for an extra week. I'm due to finish on the 27th April(a week on saturday)
He is doing some trade tests with the people on Monday.

So the question is;
Can he tell me on Monday night not to come in and take the week off as holiday?

The reason I ask is mainly that I had calculated my finances on next week's pay plus my holiday pay.

In my experience I thought as i had given notice he could only put me on gardening leave.

Hope that makes sense if not let me know and I'll try to re phase it better.

Any help greatly recived!

Matt