M/E CPL isn't at all necessary.
HOWEVER, If you are planning to do your CPL/IR/MER at the same school, then it might be worth asking if they will do you a deal on a ME/CPL.
A few years back a mate of mine was offered a ME/CPL for £1000 more than a SE/CPL so it was definitely worth while to get the extra stick time on the ME aircraft that he did his IR on.
