I'd like to Thank everyone who responded to this post for their efforts. I know from the forum that it's not just myself that is struggling with instruments and this advice is invaluable.
FMS EICAS ECAM FCC FMCADI HSI ADC APFDS CDU LNAV VNAV !! The thought of wadeing through a very heavy engineers text book isn't very appealing (the BGS ATPL notes are heavy enough) I will seriously consider Oxfords instruments notes to support my learning
Thanks again