It's cheaper drive to the coast from most cities in Britain than to take the train.
Image generated by the wonder AI system My findings are based on my own experiences. For example two hours of dual carriageway driving in my car gets you about 100 miles and a uses ⅓ of a tank, that works out as £12 in each direction. Two hours of driving will give you access to quite a lot of the Sussex or summerset coastline from London and the Thames Valley. Most train tickets to the coast cost more than £20 in each direction. Most cars have 5 seats so you can take the whole family with you.
If you have a hybrid or electric car then the difference in price is even greater.