As in your case, this is matter of 0.5 marks..you should go for revaluation..though i had applied it once and score didnt change..that was through idp..in my last attempt of sep 9 again..i missed it by 0.5 in writing and have applied eor again via British council.. waiting for the result now..Bro. I would suggest for the re check... if u re appear again then what the surety that u will be able to score the same bands in the other tasks ...