Dunno what Cav Turbos run, but the Cossie 'Yellows' aren't Bosch, they're Weber injectors, and I'm pretty sure they run one 'hole' / pintle.

I presume you've made sure the injectors are of the same impedance as the standard ones? Can't really help otherwise, although Chip knows a bit about Vauxhalls, so may be able to help.