Just had mine done at Direct Golf.
They gave them a nice clean and did a re-fit (in my case bending back to factory lies and lofts). They did it for free with one of these e-mail vouchers that encourage you to spend a fortune while you wait (I went next door and had a coffee, much to the annoyance of the store manager
).
Quite honestly I noticed very little difference, other than the grips are feeling better than they have for quite some time and they were much cleaner.
£50 seems rather steep what are they offereing to do do ? I would have thought that all they can really do is clean, maybe regrip and re-fit them. If the heads have dents and dings in them I struggle to see what they can do about it. 
Quite honestly (other than the re-fit) there was nothing they did that I could not have done.