I have resolved the issue, decided there must be something wrong with injectors, took everything off, got to number 4 and as I withdrew it it was carbon city and the jet fell off! Coupled with a blown out lower manifold gasket and seriously unhealthy looking icv I realised where the issues were.
Fitted four recon injectors, cleaned icv (extensively), replaced gasket put it all back together and TA DA! Perfect.
Thank you so much for your suggestions and theories all this info helped me a lot!