I have run the genset now for about 30 hours and I'm very pleased with the output. It charges the batteries very quickly.
A couple of days ago I let the batteries drop to 86% after a day of not running the engine and having all systems powered up.
On startup I got a charge rate of 181.6amps, this was nett as I was also drawing about 16amp/h because the heating and fridges was on. This of course soon started drop as the batteries took charge and the voltage cme up.
We have been out on the boat for the last week and a few times this week I've needed to run the genset in the evening. After a few minutes its easy to forget its on. I could certainly sleep in the bedroom with it running. This is good as when we get to hotter climes we will be able to have some AC running at night.
I still have the slow running problem to solve. To bypass this I currently have the speed sensor disconnected from the control panel but this means the genset alternator isn't charging. The manufacturers are not very forthcoming with helping me solve it. I suppose its only to be expected. I will solve it though. I have done some research and with the help of a chap that helps me with electrical stuff in the background I think I have a good insight into how the control panel works.