Is there a general way that UK courses are structured in terms of course length, contact time, class format etc.?
The short answer to your question is yes, with some big reservations. It’s a little hard to generalise, since there can be significant variances across the different universities and subject courses, and it’s worth looking at each university website to determine if the style of teaching will suit you! It’s also worth pointing out that humanities and science courses can vary a great deal in their teaching style and formats, so keep that in mind, depending on what your interests are.
Course Structure: In general, UK universities place a greater emphasis on depth in their courses, and you generally commit to a single subject (eg. history, physics, law, etc) for your entire degree, taking about 9 modules within the subject and really immersing yourself in all its detail. Note, however, that some universities may give you the option of taking modules in other fields (usually via a limited array of outside options or taking a joint honours programme). In general, it isn’t as broad as the US university approach, so if you’re looking to take a course in Eurasian empires today and one in computer science the next, you might be better off under that system! Many universities do offer joint courses today to fill the gap between closely related subjects - if you’re looking to take a joint course in philosophy and politics, for instance, that’s increasingly easy to find in UK universities. In short, if you know exactly what you’d like to study, the UK system will fit you well!
Course Length: This is fairly standard across the board - most degrees don’t take longer than 3 years, with notable exceptions for science subjects such as medicine. In general, you should expect to take about 8-9 modules within a single degree course. At Oxford, where I did my undergraduate degree, many modules can be completed within the span of a term, which is usually 8 weeks. That means about 8 tutorials per module, along with optional lectures. You will generally be expected to finish at least 1.5 modules per term, although this structure varies between universities. Some, like LSE, can spread a single module over the entire year, which means you will do the same module over all 3 terms (amounting to about 1 tutorial a week in some cases, giving you a lot of free time!). Some universities will also offer ‘half-modules’, which are taken for half the credit of a full module, but can be completed in a much shorter period of time. By and large, you’ll be assessed in a series of examinations (either taken at the end of the course or year) rather than coursework.
Teaching and Class Format: The teaching in UK universities tends to be in a small-group setting, where a professor or junior academic will teach a small group of students rather than a large class. Some universities, particularly Oxford and Cambridge, are famous for taking this further - often a tutor will teach only 1-3 students in a tutorial! Again, this varies by course and university - some popular courses can attract a larger tutorial group in some universities, and certain courses (eg. quantitative ones) may be taught via a seminar. However, the great amount of personal attention you get in settings like these make them ideal for asking questions, and filling in any gaps you encounter in your independent study. You’re also expected to be fairly independent - many tutors will set work to be completed (essays or problem sets) before a tutorial, and some will expect you to bring it to class for discussion. It’s up to you to manage your own free time and decide how much of it you’ll spend on work and play!
Contact time: This can vary a lot depending on your course - science students will probably need to spend more time in the lab, which means they will have more ‘contact hours’ in a way. Most arts/humanities students may have about 2-3 hours of mandatory contact time in tutorials per week, but apart from that you’re largely on your own! Lectures are encouraged but are largely optional (though this is not universally true of all courses), and on average I spent about 2-3 hours a week attending different lectures. I personally found that certain lectures helped me to get the basics of a module quickly, allowing me to move on to more advanced reading, but your mileage may vary - some people choose not to attend any lectures and still do perfectly well in the end!
I’ve covered a fair bit of ground here, but hope this helps - drop me a note if you have further questions!