If you want to accomplish adjustments on your Diamo Retro 150 then it is always a good idea to have a Workshop Manual to keep just for personal reference in case that you need to know simple methods to take out a specific component like the Dashboard and fit it again in the correct manner.
Diamo Retro 150 Workshop Manuals can provide specific diagnostic details for the vehicle therefore if something is playing up it can help you find out what the problem is and some ways to repair it. After that you can determine if you can do this on your own or in the event the job is just too big you could make a reservation for your Retro 150 into a suitable repair garage.
Diamo Retro 150 manual