Thanks brittep; that was a lot more information. If I read you correctly, you are really looking for what is called a 'cruiser/racer'. There are not many good ones in this class of boats and the Swan you mention is indeed one of the good examples. Other boats you should look at apart from Swan are Grand Soleil, X-yachts and Sweden Yachts (which I own). They are all superb sailing boats that you can both race in any 'round the cans' regatta and win; at the same time as they are very seaworthy boats that will go anywhere in the world (fast) in any condition. As you can probably guess: this is my personal boat type favourite.
The only problem you might have with this choice is your budget. These boats are very well built indeed and finding one for 70k GBP means that you have to search in the 20-30 years old category. Not really a problem as such as the quality is timeless, but you should know what you are looking for.