Thanks for your post and apologies for the late reply.
You have quite a comprehensive system there, but from what you have shown it should work well with the Manager30 and 12V system.
I can answer your questions through, no problems there:
1) The version of Manager30 that is released to Europe is designed to work on 230/240V AC power supply yes. We sell a different model to you, versus the USA and even Australia too
2) The amount of fusing seems mostly correct; the only addition I can see is the need for the Inverter to have one too (unless I have missed it!)
3) From what you have detailed there, I can't see any issues. The only thing I will comment on his the setup of the Battery Sensor of the Manager30 - The lead coming from it that goes to the Battery negative terminal is the only connection to be made there. What I mean there is all other negatives (loads, chassis connections etc) need to be made to the opposite side of the Battery sensor ('GND' side) only. I'll put a picture below of what I mean - it will make more sense there!
4) You will need to ground your 12V appliances to either the Battery Sensor 'GND' post or make a chassis connection. This will apply for a chassis ground connection for the inverter too - ours at least have a terminal to do so separate to the DC inputs. As far as earthing all other 240V devices to the chassis, it is best to contact an Electrician for more information there.
See what you think of the above and if you have any further questions, please let me/us know!