Chimney water damage.

Hi,
We have had some water issues with our chimney, resulting in tar dripping down onto the stove, and some paint peeling on the inside walls.

A chimney repair man has reviewed it, and doesn't think it is so bad (yet anyway). He says that our chimney cap (which was installed before we moved into the house) was missing a bit, and it was just plonked down onto the pot, and the water was getting in that way.

What he proposes to do, is the following:
- fully line chimney with 904(?) grade steel,
- including sealing onto stove,
- re-box the top and
- install a new chimney cap

He will re-spray the stove, which has been somewhat damaged by the water - it is showing some signs of rust. He said there is life in the stove yet, but advised us that if we were thinking of changing it, to do so now rather than pulling everything out again in a year or so.

My questions for people who have had experience in jobs like this is, what is a reasonable quote for the work outlined.
And are there any other questions we should ask, or things we should consider.

thanks in advance.

Chimney repairs are complex, simply installing a pipe into a chimney previously used may work or may not, the existing chimney should get a thorough cleaning and not just with brushes, If you are happy with the expertise of your guy then fine but always best to get a couple of quotes, make sure they have the correct insurance and seek references, what you suggest could work for a couple of years and then come back to bite you, I know a person in this line of work and he has some stories and pictures of jobs botched through taking short cuts.