Steady on, old chap - impugning Joe Offer's honour (and I shall refrain from the old joke punchline about '...and all night he was on 'er and off 'er!' Oops, it just slipped out, as the bishop said to the...sorry) would seem to me to come pretty close to a personal attack.
So, for the record, you're now calling Joe a liar? That's not very nice, is it?