Did some shopping uptown and got very, very lucky finding pre-owned stuff:
Rock Band Portable Drum Kit: £12.99
(THIS! was exactly what I needed. I mostly wanted that portable pedal to replace the Guitar Hero one. Even better, is that it has no loose parts, a nice curly stretch cable, (but is long enough not to reall need it), and I can use them with Rockband if I need to!
Rock Band: The Beatles £4.99
(I'm not really a fan of The Beatles, but its more songs for a cheap price!
Band Hero £4.99
(My buddy has all the other Guitar Hero games, plus Its actually got a decent setlist. Its all pop, but its not all crappy like GH5's, great game for the microphone)
Rock Band £4.50
(More songs! Plus I have the drums now)
Rock Band 3: £15
(OMG! This was a great find! This game is pretty hard to get a hold of, (there was only 1 copy in store), especially for that price! Got some great songs, plus, Rock Band eclipse Guitar Hero in DLC, so I've already got some DLC for it!
So overall spend on Guitar Hero/Rock Band stuff:
Guitar Hero: Warriors of Rock Band Pack £42
Rock Band Portable Drums Kit £13
Rock Band £4.50
Rock Band: The Beatles £5
Band Hero £5
Rock Band DLC: £10
Thing Called Love
Brutal Legend Pack
Stand Up and Shout
Child in Time
Gutar Hero DLC: £7
Black Betty (Cover)
Rocky Horror Pack (Sweet Transvestite, Hot Patootie, Time Warp)
Detroit Rock City
(NOTE: I got the Guitar Hero DLC first)
OVERALL SPEND ON GH/RB STUFF: £86.50
Man! Thats a lot!
(Well not a huge amount considering 2 brand new games would cost around £60-70, and I have most of the instruments, but its still quite hefty. Great value though, would last me quite a long time. Especially if my buddy comes over, (as he has Guitar Hero: Metallica, Van Halen, 2, 3 and Greatest Hits on 360, (he might have 4 and 5 but I can't remember)))