a 'do' is a way of saying a 'special occasion'. Usually a party.

I think the reason it's posted on the public forum means it's an open invitation to all who want to see Paul before he leaves Doha.

A Farewell DO ! lol

PS johnjos 'do tom' was his shorthand for 'party tomorrow'
PPS I posted the 8.00 p.m. comment at top of thread cos johnjo had forgotten to mention the time. OK? all clear now? :D