Thanks everyone. I don't think I'm fully satisfied with what was happening, but I'm fairly confident things are okay. Batteries have now settled at 13.00 volt, the only draw on them is 2 led lights and SG shows them at 100%.
The MPPT only has 4 battery settings, SLD, GEL, FLD and LI and I have it set to SLD. The MPPT also has an error code for over charging, but this has never shown up, so maybe SG is reading differently to MPPT?
I do only charge the leisure bank, I'll look into your suggestion, thanks.
Reading the instructions, it looks like a few of you were right about this. I think next time I come to boat, I'll have a day using the battery power, then check how the solar and SG react to the charging period.
Advice much appreciated, thank you.