My dh used to take the boys out a lot when they were young, so I could have time on my own, so when he wanted time on his own for something, I was happy to agree. He also helps out round the house and has supported me through PND and long term depression.
So, provided that there's a balance here, with the OP being happy to give his wife some 'me time' to do things without the children, as well as expecting her to take the children away so he can enjoy the grand prix, then that is reasonable.
But that's not the impression I am getting from the OP.
So how much do you do with your children, Thunderpants? Do you take them out for the morning/afternoon/day on your own? Bath them and read to them? Play with them? Do you help out round the house?
If you do, then I'd say it is reasonable to ask your wife to look after the children whilst you watch the grand prix - though I do think you'd be far better off getting the children interested in it too - just think of all the fun you'll have watching it with them in the years to come.