Best rate I found last week in Borovets was 2.73 Lev to the pound. Crown Exchange, although some others offered the same. Worst was 2.28. I just asked if I give you £100 how many Levs will you give me.
Seems best way to get cash is with a Nationwide Flex account card from the ATM. The ATM's limit you to 200 Lev per day.