Thank you for the replies guys.
I actually could bring mine back into shape with a hammer, and it looks OK now. If when I fit it, I see it is not OK, I'll cut a new one out of a 1mm aluminium plate, but I understand now that it is better to have one.
I have a 2.0i DOHC + MT75, and I had to shorten the sump above the bolts which attach the sump to the bell-housing (which will also be cut flush with the sump), so my oil sump is not attached to the gearbox anyway, and I can remove it without having to unbolt the MT75.
Thank you