S3 speedo drive

Hi there.
Does anybody have experience of removing & replacing in-situ the speedo drive spur gear from the gearbox, it looks a bit awkward to get to as its tucked right away behind the overdrive unit.
Yes it`s the gear thats failed as the speedo head works & the cable is still o.k. & not broken or the drive ends rounded off.

Thanks
jph1386