since the gearbox is already coming off. and you are already paying for labor, best to combine jobs
do all these things in one go
1) buy brand ORIGINAL new, clutch disc, pressure plate, pilot bearing and throwout bearing
2) take off the flywheel, and have it faced on lathe. do NOT use it without facing.
3) replace engine crank Main Seal with Original item
4) do plenty of cleaning where you can reach.
5) replace any accessible seals on the gearbox as well.