pretty polly - most airlines have no problems with you wearing glasses. think mainly middle eastern airlines don't allow it. but most UK based charter and scheduled airlines will not have a problem with you wearing glasses, or changing your contacts halfway through a flight.
PPL152 - some of the more fun aspects of training have to involve ditching (going to a swimming pool, normally at 5am, and hauling yourself and others into a liferaft), smoke filled cabin and slide descent. these are the more practical aspects of training. however, i think you will find with most airlines that the majority of stuff will take place in a classroom. but it is still all a lot of fun!! and you learn a hell of a lot!!