One of the biggest myths surrounding work experience is that it is unpaid, and that a wage is an acceptable sacrifice for students to make. By law, work experience of any kind should be paid at least the National Minimum Wage according to your age group. There are some exceptions to this rule, but very few in comparison to the number of work experience placements that offer inadequate payment or no payment at all.
Vacation schemes are no exception, and fortunately, it is standard practice for law firms to pay their vacation scheme students—and some of them pay very well indeed. You can see the salaries offered by each firm in the job descriptions. Some offer in the regions of £500 per week.
Hopefully this will reassure you if you would have to relocate to do a vacation scheme, or are otherwise concerned about giving up two weeks to work without being paid. Remember, if a vacation scheme isn't paying you and you're carrying out any sort of real work as part of that vacation scheme, it's not legal. The same is true of work experience.