Will the topeak FX & RX mudguards fit a Carerra kraken?
From the Topeak website, the front one attaches like this:



and the rear one like this (onto the seatpost):



so it's likely they'll both fit. 

A search for the Topeak FX Mudguard on Google Shopping gives me various ones at less than £9 as does the Topeak RX Mudguard. This place allterraincycles.co.uk appears to have both the front and rear in stock and will charge you 2 quid less including delivery, than the ebay one you're looking at.