Cheapest online appears to be about £130 (depending on platform) from Amazon. Obviously dependent on stores still having stock - High Wycombe does but I obviously don't know about others. Best thing to do is ask, they can also check other stores in the area for you.
* Limited Edition Premium Bundle contents:
* Rock Band: The Beatles game
* Höfner Bass controller (see image below) - large scale replica of the Bass famously used by Sir Paul McCartney
* Beatles-inspired and Ludwig-branded Rock Band 2 drums with classic pearl finish and vintage replica Beatles kick drum head
* Microphone Stand
* Click here for Rock Band: The Beatles tracklist (requires Adobe Reader)
* Game features:
* The Music That Rocked The World: For the first time ever, play along with 45 legendary Beatles songs on the game-disc.
* Dreamscapes & Abbey Road: Highlighting the years in Studio Two at Abbey Road Studios where The Beatles revolutionised modern recording and created amazing masterpieces are inspired artistic visual expressions known as Dreamscapes.
* Never Before Released In-Studio Audio Chatter: Audio clips featuring conversation from The Beatles' recording sessions, some of which have never before been heard, bookend the gameplay experience.
* Experiential Journey: Take an interactive journey through the legacy and evolution of The Beatles' legendary career from the renowned venues to the clothing and instruments made famous by The Fab Four.
* Venues: Progress through five seminal venues in which The Beatles performed during their careers including: The Cavern Club, the set of the Ed Sullivan Show, Budokan, Shea Stadium and the rooftop of Apple Records.
* Cut Scenes: Get whisked away through history as a montage of photos, audio and iconic Beatles moments transport you from historical venue to historical venue though the rapidly evolving look and sound of The Fab Four.
* Three-Part Harmony: For the first time ever, master the amazing three-part vocal harmonies perfected by The Beatles.
* Imagine All The People: Play with up to six bandmates... three mics for vocal harmonies, guitar, bass and drums!