It's grammar and not grammer - I was corrected on here for that!
You may of discovered PPrune isn't the best place to get advice.
'
Two reasons for pulling this one up,it should be 'it may
have not 'of'' and it is an arrogant and cras statement. All advice should be taken on board, it is obvious to your own circumstances what is rubbish and what isn't.
So one of those was a genuine mistake:
There's a 50p prize for the clever old chap who can point out the deliberate spelling mistake in this response! A bonus of a £1 will be awarded for finding the deliberate grammatical error. Answers on a postcard.
and the other was not given you have said mistake without an 's'!