I've had both a MkIV Avon and MKIV Carp refurbished in the past.
A full refurbishment is around £300 to include all the intermediate whippings too. It is cheaper to just have the handle, rod rings and ferrules sorted out. Personally I prfer the full 'monty' on my refurbishments.
My old rod builder has retired now, so cannot offer any experienced-based solutions - sorry.
Best of luck though a a fully refurbished MKIV is a joy to fish with; just don't listen to the apes from the carboniferous period LOL
PS: Paul Cook does some great work, take a look here: http://www.artofangling.net/rodrestoration.html
I've only seen his results though, never had one done by him.