I have a E series Kabola installed in my 57ft trad. It heats rads and hot water just fine. A 45 Degree bend in the chimney is the most you can get away with and then you will need to compensate with extra chimney height. You will need meths to light the boiler initially and then it is easily controlled by increasing/decreasing the fuel regulator.Maintenance is easily carried out and apart from the need to plumb in a small pump to circulate the hot water throughout the system it is pretty foolproof- or so I've found.
As previously posted, you do have to re light the boiler with meths everytime you have turned it off and this can take a few minuites. So if you wouldn't want to be involved with this start up procedure perhaps this might not be the best system for you.