I have some of the "fake" 83's on their way to me from the US, these are in fact lucas injectors and can be used in place of genuine 83's. If you were desperate for some then you could maybe order a set if you can't get the siemens ones.
FYI these can be used and mapped for a cossie, I was informed by a tuner on here who I would trust 150% and some people are running these without even knowing it.