I would be surprised if the requirement was for international experience, though this is certainly beneficial.

To get some consulting experience, try look for boutique / 2nd tier consultancies where you could apply for an internship/work experience placement. However, I don't believe that this is necessarily that helpful to get into MBB, and moving between consulting companies is notoriously difficult (though definitely not impossible). You should also look beyond consulting companies - internships in Finance or in Industry-leading firms (e.g. GSK, Pfizer) can be viewed as favourably (if not more favourably) than internships at lower-tier consultancies.

If you actually founded a company that became successful and was sold, this should be looked at very favourably by MBB. Therefore, I think the problem could possibly be more about how you display and communicate this experience, vs. lack of adequate experience.

Your CV should clearly highlight the following about your MedTech company:

- The overall objective/nature of the company (without going into great detail)

-The key challenges that had to be overcome, and the impact/results that you achieved in the end (preferably quantitative - e.g. raised series B funding of £xm, increased sales by 50%, etc.

- highlight the specific impact YOU made on the company - you need to display what the critical role you specifically had, and therefore what skills it shows.