Oil change - will this cause issues?

[VNA]

that meant I had to cut another hole in the transmission tunnel as the gearstick was now in a different position.

:lol :lol :lol

You were lucky! I used to have a Reliant Robin, that only had reverse gear working. I used to drive it backwards to work every day with a sump full of Mazola 20/50 cooking oil, and then when I got to work we had to drain it so we could fry the chips. Then going home it wouldn't start and I'd have to push it into the canal and row it all the way back again.

Steady.  For Focs Sake!  :rolleyes