Seaside towns are not nice places to live, especially when outside of Devon and Cornwall. The novelty can wear off when it rains all the time, you get crap beaches and it's bombarded with tramps etc. If you want to live by the sea then I would personally move down south, to maybe Bournemouth as you suggested. Torquay is also a really nice place to live, but again you're in Devon.
If you consider cities, Milton keynes is a nice place; it's modern and i've noticed people here are a lot less 'wild' and you can happily have your quiet life. Parts of Nottingham, Derby, possibly Lincoln and Coventry would also be good for you. Nottingham to Skegness is only around 2 hours, not the same as living by the sea but if it's close enough for a day trip, then I say it's close enough.