Hi Fiona, welcome to the Dutch forum. For information about Dutch (hall)marks see:viewtopic.php?f=5&t=32028
The maker's mark appears to be a square with; HW
for: Willem Hermanus Weenink & Zoon (Son), registered silversmith city of Zwolle 1812/1883 with 11 various maker's mark. This particular maker's mark HW
The two maker's marks of Jurrien Hendrik Wolters are in a lozenge
under 2 dots
both used 1812/1813, registered in the city of Zutphen. The lozenge shape was introduced during the time of the French regime (1795 -1813) when the French occupied, what we today call, The Netherlands.
Could you show us the object and could you check for a Dutch year letter and assay office mark/Minerva head?