...just don't expect it to definitely arrive on launch day
Halo: The Master Chief Collection | £44.08 (use code ZE310) | Zavvi
It's the Halo package we were craving this Christmas: all four of the numbered Halo titles, with Halo 2 getting the full Anniversary remaster treatment, over 100 multiplayer maps, and Halo 5: Guardians beta access to follow in December. And now it looks like UK retailers are actually being sensible about the price.
Zavvi have it cheapest right now if you're desperate to pre-order, but do be aware that they suck at getting copies out for launch day and their deliver times are laughable. Or would be if they didn't make us cry so much.