Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

I need to top up the box as I lost some when I had the drive shaft out but I cannot see anywhere obvious. Can someone point me in the right direction please.

According to the haynes manual there's a breather/filler plug at the top of the gear selector housing and a level plug at the back left of the diff housing. It's a bit cold/wet/late to go out and take my own pics right now unfortunately but hope this points you in the general area

I was wondering if that was it. Ta.