I'm going to be travelling by train for the first time in absolutely donkey's years. I'm currently out of the UK so will it be ok to just turn up at the station and buy the tickets when we need to travel or should I look into booking them online - and if so, through which website? TIA
Your local station should be able to help you book the best tickets/prices for your journey. Or look at National Rail - please don't go through intermediaries like the Trainline - they are unnecessary, because you can access the information directly from the provider, and they just put an extra level inbetween you and the provider. And they don't do this out of the goodness of their hearts, either. They are making profit, and that profit, presumably, either comes from the purchaser or from the rail companies.
Book in advance, the tickets really are cheaper than paying on the day, and not just by a couple of quid either. Can sometimes be cheaper to split the journey and only buy singles. Find out the train operator for the route and go through them. Trainline etc only offer what the operators say they can, and are either the same price or because of charges cost more.