Unless you have a pressing need I'd wait until next summer and head off to Beltring or similar. You'll get to make your own choice on what constitutes a good 'un and you won't have to pay postage.
Obviously I don't need to remind anyone on this forum that adapting de-acs to functioning airsoft weapons is highly illegal and that doing so will probably get you jail time 
you can buy woodwork and bands etc without the need to take-down a deac.
even if i just use the wood work and various fittings?
the breech and barrel and bolt ect will just be removed and stored
Depends if they're already part of a gun that has a Proof House certificate. If not, then you're fine (that's the basis of Shoot 'n' Scoot's products). If so then you are technically in breach of the law. Sure it makes no sense, but considering the draconian laws we have at present it's a safer bet to construct your custom gun from NOS spares than adapting a de-ac.
EDIT: If anyone is in doubt about just how seriously the cops take this stuff, here is a post from 2008 from an old skool CiA member:
my house was searched by the police. due to the amount of airsoft gear, and an MG42 de-ac they had the whole lot- white tents, armed guards the lot. neighbours thought i'd been murdered. I was re-arrested under the terrorism act and violated in many 'less than happy' ways....The firearms division went through my house like bad dose of the shlits and I was interviewed extensively over 24 hours about the various uniforms i had and the different firearms in my house. They were specifically interested in my previous army career(which involved armourer) and my knowledge of repairing and rebuilding weapons. They knew EVERYTHING about my life and my army career after about 15 hours. After finally being allowed to speak freely and explain what I was using the de-ac for I was told they thought I was reactivating firearms using the knowledge i'd gained in the forces.
Surely cheaper to buy a D-boys K98 for the external parts than a deac?
You've got nothing to ein, zwei, drei, vier
