twiglett, we have done the opposite and reinstated loads of walls. What we've done in our kitchen is to have a 'psychological' divide - i.e. there is a wall, but there is a big arch doorway in it, with no doors, so that you can feel like you've left the working area to come into the eating area. I really like it like that, and as someone said, future purchasers may have different ideas, so it is worth keeping your options open. Also, if you were selling the house, it always looks good to have a large number of downstairs rooms. (We have changed ours from 1 large reception room and long kitchen to kitchen and 3 reception rooms just by building a few walls).
We did some major work to the structural walls in our house, and I would recommend either getting a friendly engineer to do you some drawings, or getting an architect to do it. The advantage of an architect is that they often will recommend builders, and as the builder won't want to hurt his reputation with the architect, he will usually do you a good fair-priced job. There will probably be some calculations to do as well as regards lintels etc. We just did ours ourselves, with some help from a friend, but dh and friend were both engineers. I think the drawings need to be submitted to the buildings reg. people, and then they come and do an inspection while the work is taking place and give you a certificate. Can't remember what the fee is, but it's not extortionate. This is very useful when selling the house!