Having seen your other thread: Do you really need an accountant at this stage? If you are planning a business plan for a potential hostel, you would certainly benefit from help from people who know what sort of incomes and expenditures a hostel would incur. Accountants become needed after you have got going and may need help with how to analyse your figures and present them in the most tax-efficient way, and they don't really need to have a deep knowledge of hostels to do that.
If you are planning a quality friendly hostel in London, I would be very interested in following your developments and could help you with financial suggestions. For my website www.uktrail.com , I plan to visit hostels in London in the near future, so I may gather some useful background knowledge!