If you want to perform fixes on your own Diamo Retro 150 then it is always recommended to have a Workshop Manual to keep just for a guide if you need to know the way to take off a particular component for example the Dashboard and install it again the right way.
Diamo Retro 150 Workshop Manuals can offer you specified diagnostic information on your car therefore if something is wrong it can help you work out what the problem is and how to resolve it. Then you are able to determine if this can be done by yourself or in case the job is too big you can make a reservation for your Retro 150 in with a decent repair garage.
Diamo Retro 150 manual