Comparing a couple of Carrera bikes

Both of the following bikes are on offer at Halfords for £299 the first one is down from £499 and the second £599
I prefer the look of the TDF but as the Zelos is half price I'd like to make sure I get the best one. Could somebody please tell me why the difference in the original prices?
Thanks in anticipation
Jimi Pop
Carrera TDF Road Bike 2011/2012 - Medium 54cm
vs
Carrera Zelos Limited Edition Road Bike 2012 Medium
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_810691_langId_-1_categoryId_165710#tab2
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_888023_langId_-1_categoryId_165710#tab3
I prefer the look of the TDF but as the Zelos is half price I'd like to make sure I get the best one. Could somebody please tell me why the difference in the original prices?
Thanks in anticipation
Jimi Pop
Carrera TDF Road Bike 2011/2012 - Medium 54cm
vs
Carrera Zelos Limited Edition Road Bike 2012 Medium
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_810691_langId_-1_categoryId_165710#tab2
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_888023_langId_-1_categoryId_165710#tab3
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