I've searched through some topics about changing the batteries and key fobs but still haven't answered the question that I have.

 

Both of my key fobs are looking pretty tired and the bodies look quite reasonable to replace. I've found videos on the net which show in detail how you replace either just the battery or the entire internals. 

 

So, if I transfer the entire contents of the key fob to a new body (including the key blade itself), will I need the key to be recoded using VCDS or will it work with the new body?

It will all work with the new body, my wifes key for her Beetle a couple of years ago was all beat up so bought a new body, transferred it all over and worked a treat and looked brand new!  Got mine on ebay for a few quid.

you may have to resync the remote to the central locking which is easy to do as there's a manual procedure for this which is usually shown in the owners manual. It can be done with VCDS as well

take care with the small glass phial  it's probl'y glued and VERY fragile     only do one key at a time so you don't get stuck

Many thanks for all the replies so far. I think I'll take the plunge and invest in 1 and see what happens. Only doing 1 at a time is a very wise piece of advice.

Best way (apparently) to get the small glass bead (this it the transponder chip that's paired to the immobiliser) is to carefully apply nail varnish remover to dissolve the glue. DO NOT attempt to prize it out, it will shatter.

 

take care with the small glass phial  it's probl'y glued and VERY fragile     only do one key at a time so you don't get stuck

agreed! doesn't take much to break them