alias mc='export LANG=en_GB; mc'
This will first switch the LANG locale to en_GB (or if you prefer you can use en_GB.ISO-8859-1) and then run MC. this way your default console stays UTF8.
You can add alias definition to bashrc (user's or global/systemwide):
echo "alias mc='export LANG=en_GB; mc'" >> .bashrc
echo "alias mc='export LANG=en_GB; mc'" | sudo tee -a /etc/bash.bashrc
echo "export LANG=en_GB.ISO-8859-1" | sudo tee -a /etc/bash.bashrc