My suggestion where to do it if you want great training is with Alan Cassidy at White Waltham / WLAC:
Aerobatic Training, Pitts Training, Aerobatic School Have done a week-long BAeA/AOPA course with him on a Pitts and it was great. Just as good as his book. You need to find someone who great at 2 things: their own aerobatic flying, but also being a great teacher. Many are former, few are latter at the same time as well. Could not had a better teacher than Alan.
White Waltham is also a great place being close to Heathrow when coming from abroad.
That said, I am still waiting to see if the Estonian CAA will accept the course to issue the FCL.800 proficiency, as WLAC although an ATO does not have aerobatic training on it's certificate. You can argue, if that is needed or not, at the end of the day it depends on the people and regulations in your local CAA.