dont molest it with a screwdriver, tap it out properly - you will have to make a tap (easy), then you wont score the housing.
use a thick piece of wire and make a hook on one end, overbend
it a tiny bit, then make a stopper on the other end and put
a heavy weight inbetween, eg a 1/4 pound hammer head. tap it
evenly and a few times, then its out.
then press in the new seal with wd40 and your fingers or tap
it in with a suitable socket.
if you tap it then all you have to do is drain the oil
and the remove tailshaft which is less work.