Have you been given the actual plaque or that tatty photo Pete?

If you have the actual plaque then photograph it at high resolution & then try the auto trace, it's not that complex so a high rez image should define the edges reasonably well.
You may need to play about with the auto trace as the default settings don't always give the best results, said this on another thread if you want to do this sort of work then you really need to learn how to node edit & get the best out of any trace or vectorising software that you use.
If you have just been given that picture then you will have problems unless you know how to use the software properly. Go back to who ever gave it to you & ask for a higher resolution image.