There probably will be lead at the back of your chimney, but it will be covered by the slates, usually the lead forms an apron around the chimney. difficult to explain without drawing it, but does'nt sound like you've anything to worry about. There is some more info on this site, just follow this link: //www.diynot.com/pages/rg/rg031.php
Hope that helps...
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local