Two things I'd want to know would be the date of the "date hereof", ie is the 99 years still existing.
Do you only need to make connection to existing pipes etc... under the land or put new pipes etc... under it?
I'd also want confirmation of who has the benefit of the reservation of easement to make sure whether it's you or not.
Without seeing all the documents and checking out some other issues I'd not want to comment at this stage.
I'd also want to know what you intend doing with the land and, if you need planning, what conditions they may put on.
You might find this interesting...
http://www.practicalconveyancing.co.uk/content /view/10129/1116/
Was there ever anything on the land before and anything which has required any form of water, drainage etc...
Have you spoken to the relevant utility providers about the practical issues relating to connection?