Original post by aadil10I study civil engineering at Leeds so I can't speak for those two universities, but generally speaking most engineering courses have pretty standard, generalised modules in the first two years, with maybe a couple of optional modules in second year. This gives you a well-rounded knowledge of the subjects so that you have chance to switch between the different degrees under that faculty (e.g. I could switch to Architectural Engineering before the end of second year). Third year is where you'll have a good idea of which parts you like and start to specialise more and even more so in fourth year.
In terms of which type of engineering to do, there is no major 'benefit' to any type, except for personal opinion on which industry is more lucrative to be in when you graduate. Ultimately, any kind of engineering is a very useful degree, mostly due to the analytical skills you gain which many industries love. It's no surprise that so many engineers go into finance related jobs after graduating. It sounds cliché but do what you enjoy. Take a look at the modules you'll be studying each year for the degrees you're interested in, they'll be on the university websites.
Civil is all about buildings and structures. The maths is mostly statics, using design codes to size beams,columns,foundations, etc. You'll design your own hypothetical structures and draw them in CAD. There's structural, water, geotechnics, environmental, project management. These are what you'd specialise in after second year. Mechanical I haven't studied but there'll be similar pure maths initially, and I'm assuming a lot of dynamics, thermo, etc as well as their own CAD work.