I bought mine of ebay off a refridge specialist.My condenser was shot full of holes,spoke to the refridge guy and he wouldnt sell me one without a new drier and a new thermostatic valve.He reckined as it had been woofed for so long that the drer would be u/s that would knacker up the thermostatic valve and then woof the consenser.
Changed them all myself,pretty easy stuff considering some of the other jobs on them. Cost me 149.00 inc vat ,two year warranty if i fitted the lot. had euromaster suck it all out then,left it for a good hour no leaks then they added oil,gas etc all for £29.99 ,pretty good i thought,aircon works fine now and no blessed book symbol comes up.
oh btw they told me not to bother with new o rings ,just put plenty of wd 40 on them and refit after a couple of minutes,their words not mine,hope it helps