An overseas friend of mine just failed her Master in Law exams at one of the top UK Universities.  Does anyone know whether she can be accepted anywhere else to do some extra work and sit exams in Summer/Autumn this year?

I've never heard of that being offered. Your friend should consult with her university which may offer re-examinations.

I don't think this is possible either (ie you cannot transfer credits from other universities).

Your friend's UK university will usually offer at least one re-sit opportunity. Some universities will offer re-sits within a few months and some will require the student to sit the exam again the following academic year (eg LSE). It might be possible that the university will allow your friend to sit the exam at an authorised exam centre in her home country.

Fantastic! Thanks everyone!