Mazersteven is correct the center should match the fronts to maintain timbre ( seamless sound).
You should look at the matching Wharfedale Evolution Cetner. Here is one you might want to consider, Wharfedale Evolution 2 Center Channel Speaker, Successor to the Acclaimed Pacific Evolution Loudspeaker for $509,95
http://www.wildwestelectronics.net/wharfedale-evo2-center-channel.html
specifications:
Specification
Bass Driver 2x 125mm 2 way
Soft Dome Tweeter 1x 25mm
Nominal Impedance 6 Ohms
Frequency Response 80Hz - 43kHz
SPL 1W @ 1m 89dB
Max peak SPL 108dB
System Fb 70Hz
Crossover Frquencies 2.2kHz
Dimensions H x W x D (mm) 170 x 422 x 296
These specs look very close to you number 2 choice.
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Here are some other Wharfedale Center speakers:
http://www.wildwestelectronics.net/wharfedale-center-channel-speakers.html
Since they are from the same vendor there timbre might not match exactly , but should be close.
Good Luck!