Thank you, as always if one had the time, money and a blank canvas…
I am simply trying to optimize what I have without spending a huge amount for a full refit/modifications and most of it is fairly new, even the 4 x 220Ah AGM’s were new only 3 years ago and are performing faultlessly (the only let down is the old Multiplus with the power assist seeming not to work, but as I asked, that might just be a settings issue)
The LiFePO4 batteries are less than 2 years old and are still in good condition, and as they only run the onboard 230VAC, I am very happy, for redundancy, to keep both the systems working as best I can set them up.
I believe the 3(2.5)kW at 12V on the original Multiplus would be perfectly adequate if the power assist were working to give a combined 5.3kW when the genset is running, which is, from what I can ascertain how the boat was originally set up back in 2009… hopefully some of the suggestions by @pwfarnell will help me get further down the trrack!