I dug out my plans, cause now I'm curious about this.

The firewall is laminated from 14/13. The cutout is off center a good bit to the right. The next is former 5/6 and it has the tankbox cutout also offset to the right.

The instructions here say "ensure that the assembly is handed correctly". I think that is the funny Brit way of saying make sure you get the right handed side of the formers on the right hand side etc.

So you might want to check former 5/6 to make sure it is not in backwards. I once built two left handed wings on a Midwest Stearman, so don't feel too bad if it's backwards.