Thanks everyone. Reading all your comments, and talking to DH last night (he basically told me I was a stress head!) I'm sure that any annual leave he takes does not need to be taken into account.

What was worrying me was that they can ask you to sign a statutory declaration and part of that is meant to be how much leave your partner is taking. I didn't want to say three weeks, and then have it slip out at work that he was going to be with me for two months, so they would think i lied!!

But it sounds like it's all good and above board.

Thanks again!