I am not radically different from MickV
Enjoy the flight over, having a brief nap if your body tells you to do so. Get to Vegas early evening, check-in to hotel, shower, get on it! Keep going as long as you can - I usually make it to 12.00 local time the next day. Go to bed. You are now essentially on UK-time. Get up at 21.00 and enjoy Vegas until early afternoon the next day. Repeat for as long as you are there.
Your flight back means staying up for a bit longer on your last day - 24 hours or so - nightcap if you can face it, sleep like proverbial baby all the way back to UK. I'm usually back at work next day and am fine. With 2 days to recover, even if you have the mother of all jet lag, you will be well recovered by day 3.
Enjoy!