Jacko - the 177T RTOW figure was, I believe, an unofficial figure based upon the actual 090/08 wind passed to the crew with their take-off clearance - not the pre-flight calculated value using the ATIS conditions at that time.
We introduced 'late change' data for the Vulcan in 1978 specifically to allow for last minute wind/temp/pressure changes influencing the V speeds - and it's something we teach our VC10 students during their simulator training. It is absolutely fundamental on heavy transport category aircraft to recompute RTOW if the weather values are different to the planned values on departure; equally it is never acceptable to ignore RTOW or max permitted take-off weight limits. I would be very, very unhappy at ever flying in an aircraft whose crews seemingly ignore such limits......