Yes and no - after changing the prop centre bearing there was still a lot of vibration and noise which was traced to the gearbox output shaft bearing/bushing and seal.
These components were renewed and then the high speed run on axle stands was conducted.
You see, the first time after renewing the prop centre bearing, there was a lot of strange vibration that was simply down to the prop centre bearing being slightly out of line on its mounting plate. The bolts were slackened and the car driven slowly round the block and the bolts tightened again, problem solved, except for the noise/vibration from the gearbox output shaft.
Once the extension housing/tailshaft/output shaft bush and seal were renewed it ran successfully at low speed on the stands so i brought the speed up. The only slight vibration and bit of noise is now coming from a slightly worn differential but it has done 220,000 miles so it's allowed to be a bit worn/noisy.
I may see if i can find a younger diff or back axle to fit instead but for the time being, i may try one of the additives that are designed for noisy diffs.
I'm not a big fan of additives in general but they have their place sometimes, usually when they alleviate symptoms that that are annoying rather than dangerous and would take a lot of work to sort out for what would be very little gain.
Meanwhile the diff oil is clean and looks reasonably young, no obvious trace of swarf or similar and is only a mild whine so easy to live with. Overall the car is now very quiet with wind noise being the biggest intrusion.
